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  • Articles  (20,196)
  • Springer  (19,078)
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  • 1975-1979  (20,196)
  • Geosciences  (12,242)
  • Process Engineering, Biotechnology, Nutrition Technology  (7,954)
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  • Articles  (20,196)
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  • 1
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    Journal of chemical crystallography 9 (1979), S. 57-65 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Orthorhombic crystals of the title compound, C7H16ClNO2SSn, belong to space groupP212121, witha = 6.658(5),b = 10.974(3),c = 17.144(5) Å, andZ = 4. The diffractometer data, measured with CuKα radiation, has been refined to anR index of 0.053 for 1110 observed terms. The geometry about the Sn atom in the monomeric complex units is distorted trigonal bipyramidal; the N and Cl atoms are in the apical positions, and the Sn lies at 0.107(1) Å from the equatorial plane. The Sn-Cl, Sn-S, and Sn-N bonds have lengths 2.523(4), 2.413(3), and 2.434(12) respectively, and the angle N-Sn is 166.9(3) °.
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  • 2
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    Journal of chemical crystallography 9 (1979), S. 87-105 
    ISSN: 1572-8854
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    Topics: Geosciences , Physics
    Notes: Abstract The effects of hydrogen bonding on the geometry of the carboxyl group have been studied systematically based on accurate X-ray crystallographic data. In general, the C-O(H) bond length increases with increasing O ⋯ O hydrogen-bond length, while the C=O bond length decreases. These variations become less pronounced for longer O ⋯ O distances. The O=C-O(H) and C-C-O(H) angles decrease with increasing O ⋯ O separation, while the C-C=O angle increases. The sum of the three angles remains close to 360 °, testifying to the planarity of the carboxyl group. These correlations are not observed to hold for cyclic hydrogen-bonded dimers, indicating that a continuous variation in the degree of disorder of the protons may be present, ranging from the ordered case with easily distinguishable C=O and C-O(H), to the 50%-50% disordered case, where the two C-O distances become equal.
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  • 3
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    Journal of chemical crystallography 9 (1979), S. 135-141 
    ISSN: 1572-8854
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    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP21/c, witha = 8.849(4),b = 13.798(5),c = 7.943(4) Å, β = 102.98(3) °, andD x = 1.85g cm−3 forZ = 4. The finalR factor for 1283 observed reflections is 0.046. The aluminum atom is bonded to the nitrogen atom of the thiocyanate ligand, where the Al-N bond length is 1.94(1) Å. The SCN is linear, and the C≡N-Al angle is 175(1) °. The cesium ion exhibits four contacts less than 3.60 Å: Cs ⋯ C(thiocyanate) = 3.39(1) Å, Cs ⋯ C(methyl) = 3.52(1) Å, Cs ⋯ C.(methyl) = 3.56(1) Å, and Cs ⋯ N = 3.575(9) Å. The closest Cs ⋯ S is 3.772(3) Å.
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  • 4
    ISSN: 1572-8854
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    Notes: Abstract The crystal structure of fentanyl has been determined as part of a structure-activity relationship study on a congeneric series of 4-anilinopiperidines. The compound crystallizes as a citrate toluene solvate, C22H28N2O · C6H8O7 · C7H8, in the monoclinic space groupP21/c witha = 18.292(6),b = 9.825(4),c = 19.479(4) Å, β = 107.43(3) °, andZ = 4. The structure was solved by direct methods using the program Simpel, and refined by block-diagonal least squares to anR value of 0.092. The torsion angle that describes the conformation of theN-phenyl ring relative to the piperidine ring is 123 ° and differs from that found in other 4-substituted anilinopiperidines (172–177 °).
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  • 5
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    Journal of chemical crystallography 9 (1979), S. 173-179 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of 5-amino-1,2,3,4-thiatriazole has been determined from three-dimensional counter data and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP21/n witha = 3.780(2),b = 10.179(5),c = 10.139(5) Å, β = 91.78(4) °, andD x = 1.74 g cm−3 forZ = 4. The finalR factor for 572 observed reflections is 0.042. This structure represents the first X-ray structure determination of an ammosubstituted thiatriazole, although electron diffraction and CNDO calculations have been carried out on related systems. The results show that the discrepancy between the observed reactivity and that calculated might be due to the fact that 5-substitution appreciably affects the π-system of the heteroaromatic ring.
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  • 6
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    Journal of chemical crystallography 9 (1979), S. 219-221 
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  • 7
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    Journal of chemical crystallography 9 (1979), S. 199-217 
    ISSN: 1572-8854
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    Topics: Geosciences , Physics
    Notes: Abstract Crystals of the 3β-acetoxy derivative of α-amyrin are monoclinic, space groupP21 witha = 8.021(1),b = 11.474(1),c = 15.564(2) Å, and β = 100.496(3) °. Crystals of the 3β-benzoxy derivative are orthorhombic, space groupP212121, witha = 6.752(1),b = 12.974(1), andc = 36.664(3) Å. Both structures have been solved by direct methods and refined by full-matrix least-squares, using data collected on an automated four-circle diffractometer. The final residuals for the acetoxy and benzoxy structures are 0.055 (2274 significant independent reflections) and 0.152 (1220 significant independent reflections) respectively. The geometry of the α-amyrin skeleton in both structures is similar to that found in other triterpene structures containing a system of five condensed six-membered rings. RingC has a C(8)β-sofa conformation due to the presence of the double bond at C(12)-C(13) whereas in the remaining rings thechair conformation predominates.
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  • 8
    ISSN: 1572-8854
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    Notes: Abstract Both of the title compounds crystallize in the monoclinic system: C23H17NO2 (Ib),P21/c,a = 8.970(1),b = 22.629(5),c = 9.101(1) Å, β = 106.08(1) °,Z = 4,D x = 1.27 Mg m−3; C19H17NO2 (Ic),P21/a,a = 15.225(2),b = 6.429(1),c = 17.190(1) Å, β = 112.99(1) °,Z = 4,D x = 1.25 Mg m−3. The structures were solved and refined by standard methods, both toR ≈ 0.04. In compound Ib, a weak intramolecular interaction is observed between the nitrogen atom from the isoquinoline ring and the carbon atom from the carbonyl group, with the N(2) ⋯. C(18)distance being 2.98 Å. In compound Ic, the PhCO2 -fragment is twisted in the opposite direction to that in compound Ib, without hydrogen bonding. The pK′ a and IR data were considered in the light of the results of the X-ray investigation.
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  • 9
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    Journal of chemical crystallography 9 (1979), S. 281-282 
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  • 10
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    Journal of chemical crystallography 9 (1979), S. 295-304 
    ISSN: 1572-8854
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    Topics: Geosciences , Physics
    Notes: Abstract Chloramphenicol, C11H12Cl2N2O5, is orthorhombic, space groupC2221,a = 17.495(3),b = 7.321(2),c = 22.130(4) Å, andZ = 8. The structure was solved by direct methods and refined to a finalR value of 0.068 for 1186 counter-reflections. Estimated standard deviations for bond lengths and bond angles involving nonhydrogen atoms average 0.009 Å and 0.6 °, respectively. All the hydrogen atoms that are bonded to O or N and are available for hydrogen-bond formation take part in the hydrogen-bonding network. The crystals become brown in color on prolonged exposure to X-rays and γ-rays. Our structural investigation with colored crystal does not indicate any structural change.
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  • 11
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    Journal of chemical crystallography 9 (1979), S. 317-323 
    ISSN: 1572-8854
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    Topics: Geosciences , Physics
    Notes: Abstract C24H21N3O2 is orthorhombic,P212121,a = 15.1342(3),b = 14.1692(3),c = 9.6533(3) Å,Z = 4,D m = 1.23 g cm−3. The structure was solved by direct methods, and refined to anR of 0.048 (R w = 0.068) for 1831 observed reflections. An intramolecular hydrogen bond is present. The conformation of the seven membered ring is boatlike with a quasi-mirror plane through N(1).
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  • 12
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    Journal of chemical crystallography 9 (1979), S. 329-338 
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  • 13
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    Journal of chemical crystallography 5 (1975), S. i 
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  • 14
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    Journal of chemical crystallography 5 (1975), S. 81-82 
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  • 15
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    Journal of chemical crystallography 5 (1975), S. i 
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  • 16
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    Journal of chemical crystallography 5 (1975), S. 113-119 
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  • 17
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    Journal of chemical crystallography 5 (1975), S. 93-100 
    ISSN: 1572-8854
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    Notes: Abstract The crystal structure of the title compound, (CH3)2Sn(C6H4O) CHN(OC6H4), has been determined from X-ray diffractometer data by Patterson and Fourier methods. The crystals are orthorhombic, space groupPbcn witha =19.304,b = 10.534,c = 13.398 Å andZ = 8. Full-matrix least-squares refinement of the 1024 reflexions having ¦F¦2 〉σ(¦F¦2) led toR = 0.044. The tin atom is pentacoordinate with the two oxygen atoms forming the apices and the two methyl groups and nitrogen atom forming the equatorial plane of a distorted trigonal bypyramid. The Schiff base ligand is thus tridentate. The bond lengths involving the tin atom are Sn-O, 2.108(6) and 2.130(6); Sn-N, 2.224(8); Sn-C, 2.10(1) and 2.12(1) Å.
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  • 18
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    Journal of chemical crystallography 5 (1975), S. 83-92 
    ISSN: 1572-8854
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    Notes: Abstract The crystal structure of tetraphenylarsonium nitridotetrachloroosmate(VI), (Ph4 As)[OsNCl4 ], has been determined from three-dimensional X-ray diffractometer data. The crystals are tetragonal with unit-cell dimensionsa = 12.667(3),c = 7.820(2) Å, space groupP4/n andZ = 2. Full-matrix least-squares refinement, using 1189 independent reflections, has reachedR = 0.037. Two discrete ionic species are present in the structure. The [OsNCl4]− anion has 4mm (C 4v) point symmetry, and the osmium atom has a square-pyramidal coordination with Os-N and Os-Cl bond lengths of 1.604 and 2.310 Å respectively. Because of the strongly π-donating nature of the terminal nitrido ligand the basal plane is depressed to 0.58 Å below the osmium atom, such that the N-Os-Cl angles are 104.5 °. The tetrahedral tetraphenylarsonium cation has ¯4(S 4) crystallographic symmetry with As-C distances of 1.912 Å and two independent C-As-C angles of 105.1 and 111.7 °.
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  • 19
    ISSN: 1572-8854
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    Notes: Abstract The mixed crystal ofL-threonine andL-allothreonine is orthorhombic, space groupP212121, witha = 13.60(1),b = 7.87(1),c = 5.16(1) Å andZ = 4. The structure, which is closely isomorphous with that ofL-threonine, was solved from photographic data and refined to anR of 11.6%. The structure is spatially disordered, containing the molecules in bothL- andL-allo forms.
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  • 20
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    Journal of chemical crystallography 5 (1975), S. 121-123 
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  • 21
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    Journal of chemical crystallography 5 (1975), S. 125-128 
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  • 22
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    Journal of chemical crystallography 5 (1975), S. 129-135 
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  • 23
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    Journal of chemical crystallography 5 (1975), S. 137-140 
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  • 24
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    Journal of chemical crystallography 5 (1975), S. 141-143 
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  • 25
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    Notes: Abstract The structure of triphenylphosphine — (1 — (di(trifluoromethyl) — hydroxymethyl) — cyclopentadienyl) — (1,2 — di(carboxymethyl)ethylene — 1 — yl) — ruthenium (0) has been studied by single-crystal X-ray diffraction techniques. This compound, [C5 H4(CF3)2 COH] Ru(PPh3)C2(CO2Me)2H, crystallizes in the triclinic space groupP¯1 witha =10.131,b= 15.107,c= 10.798 Å, α = 102.14,β = 107.04, γ = 89.64° andZ = 2. The structure was refined by block-diagonal least-squares methods to a finalR value of 0.042, including hydrogen atoms. The compound contains a dicarboxymethylethylene ligand coordinated to ruthenium both through a ketonic oxygen and through a metal-β-carbon σ-bond. An intramolecular hydrogen bond is observed. Details of the structure are reported, and the structures of several Ru(0) complexes are compared.
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  • 26
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    Journal of chemical crystallography 5 (1975), S. 177-189 
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    Notes: Abstract The structure of hexahydro pyridine (piperidine), a compound of psychobiological importance, has been determined in the form of its hydrochloride by the heavy-atom technique, using three-dimensional X-ray data. Hexahydro pyridine hydrochloride, (C5H5N)H6.HC1, crystallizes in the orthorhombic space groupPbcm with four molecules per unit cell of dimensionsa = 9.68(2),b = 7.30(3),c = 9.67(2) Å. The positions of the hydrogen atoms were located from a difference-Fourier synthesis. The structure was refined by the full-matrix least-squares method, using anisotropic temperature factors, leading to the finalR-value of 0.094. The hexahydro pyridine ring has a chair conformation. The crystallographic mirror plane atz = 1/4 coincides with the molecular mirror plane passing through the C1, N and C(3) atoms of the molecule in such a way that C(1)′ and C(2)′ are the mirror images of C(1) and C(2). The dihedral angles which plane I, containing C(1), C(2), C(2)′ and C(1)′, makes with plane II, containing C(2), C(3) and C(2)′, and planeIII, containing C(1), N and C(1)′, are 120.47 and 116∶42 °, respectively. The molecules are held together by a network of hydrogen bonds of type N+ —H ... C1− in thexy-plane, and by van der Waals forces in thez-direction. Both the hydrogen atoms in the NH 2 + group of the molecule take part in the formation of hydrogen bonds.
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  • 27
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    Journal of chemical crystallography 5 (1975), S. 203-214 
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    Notes: Abstract DL-allothreonine hydrobromide belongs to space groupP21/c with unit-cell dimensionsa = 8.91,b = 7.78,c = 18.91 Å and β = 92.0 °. The structure was solved by the heavy-atom method and refined to anR-index of 10.7%. There are two molecules in the asymmetric part of the structure having different conformations.
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  • 28
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    Journal of chemical crystallography 5 (1975), S. 215-226 
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    Notes: Abstract The crystal structure of CaSO4 · 4(CH4N2) has been determined from 2695 x-ray intensities measured on a diffractometer, and refined anisotropically to anR-factor of 0.059. The pseudotetragonal crystals contain linear chains of CaSO4 which strongly resemble those in other CaSO4 phases. A common dodecahedral coordination of calcium ions in all these phases is demonstrated, and its implications in the conversion from one phase to another is discussed.
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  • 29
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    Journal of chemical crystallography 5 (1975), S. 247-256 
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    Notes: Abstract The crystal and molecular structure of pyridinium di-μ-oxo-bis(oxodichloroaquomolybdate(V)) monohydrate has been determined from MoKα diffractometer data. The compound crystallizes in the monoclinic space groupP2 1/m witha = 7.544(1),b= 17.046(3),c = 7.894(1) Å, β = 106.00(1) ° andZ = 2. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares method toR = 0.046, using 1800 reflections for whichF〉 4σ(F). Molybdenum atoms are linked by the double oxygen bridge with an Mo—O distance of 1.943(4) Å and an Mo—O—Mo angle of 83.4(2) °. The Mo—Mo distance is 2.584(1) Å, indicating direct Mo—Mo bonding. The pyridinium and [Mo2O4C14(H2O)2]2- ions are hydrogen bonded through N—H ... O bonds. The N ... O contact is 2.656(8) Å.
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  • 30
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    Journal of chemical crystallography 5 (1975), S. 257-266 
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    Notes: Abstract The structure of the title compound C13H9Br2N has been determined with MoKα1 diffractometer data, and refined by full-matrix least squares toR = 0.061 for 888 observed reflections. The crystals are monoclinic: space groupP21/a,a = 24.912(13),b = 5.877(1),c = 4.046(1) Å,β = 92.42(3) °Z = 2. The uv absorption spectrum indicates a nonplanar conformation in solution. In the solid, the molecule is disordered about a crystallographic inversion center and is planar to within 0.045 Å.
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  • 31
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    Journal of chemical crystallography 5 (1975), S. 227-245 
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    Notes: Abstract Both the methanol and hexanol adducts of tris(8-quinolinolato)manganese (III) have been shown to be isomorphic. They crystallize in the monoclinic space groupP21/n with four molecules in the unit-cell. The cell dimensions of the methanol adduct area= 10.847(3),b= 13.201(4),c= 17.285(5) Å β = 97.56(5) °; the asymmetric molecular unit being Mn(C9H6NO)3.CH3OH. For the hexanol adduct,a =11.201(4),b=13.342(4),c = 17.200(5) Å, β = 97.09(6) °, with an asymmetric molecular unit, Mn(C9H6NO)3 · 1/2(C6H13OH). The methanol adduct structure was deduced from CuKα. intensities visually estimated from Weissenberg films, but refined on data rerneasured on a four-circle diffractometer. Data measured with Mokα radiation on a diffractometer was used for the analysis of the hexanol adduct. Both structures were solved by the heavy-atom method and refined by difference and least-squares procedures. AnR of 0.079 for the 1536 observed terms of the methanol structure and anR of 0.063 for the 2509 observed terms of the hexanol structure were attained. The complexes are in themeridional conformation, with the manganese atoms coordinated to the bidentate 8-quinolinol ligands in a distorted octahedral configuration. In the methanol structure, two methanol molecules related by the crystallographic center of symmetry lie in a “cage-like” cavity in the crystal structure, whereas in the hexanol structure only one hexanol molecule is so accommodated. The latter is disordered, the crystallographically imposed symmetry requiring that it adopts two orientations in the unit-cell.
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  • 32
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    Notes: Abstract The crystal and molecular structure of (±)-1-methoxycarbonyl-1-hydroxy-2-oxa-3,4-dioxo-7-methoxy-9-methylcyclopenteno[3,4-c] chromene (“Altox,” II) has been determined by x-ray crystallographic methods. The crystals are monoclinic:a= 10.748,b = 9.644,c= 13.845 Å, β = 104.58 °,Z = 4,P21/c. The structure was solved by direct methods and refined by full-matrix least-squares on 1158 symmetry-independent ¦F 0¦-data toR = 6.9%. The molecules are linked by hydrogen bonds (O...O = 2.74 Å), forming a chain-like structure.
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  • 33
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    Journal of chemical crystallography 5 (1975), S. 279-285 
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    Journal of chemical crystallography 5 (1975), S. 295-303 
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    Notes: Abstract 4-Amino-4-carboxylthiapyran hydrobromide crystallizes in the monoclinic space groupP21/m, witha= 9.72 Å,b= 6.60 Å andc=7.10 Å,β = 94.8 ° andZ= 2. The structure was solved by the heavy atom method with 786 observed reflections and refined to anR of 0.076. There is an interesting weak interaction which the hetero sulfur atom of the thiapyran ring makes with a symmetry related amino nitrogen (N...S distance 3.34 Å) which significantly affects the “puckered-chair” conformation of the thiapyran ring.
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  • 35
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    Journal of chemical crystallography 5 (1975), S. 287-294 
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    Notes: Abstract 1,1′,3,3′-Tetraphenyloxaldiamidrazone, C26H24N6, crystallizes in the monoclinic system: space groupP21/c,a= 13.946(1) Å,b= 5.706(1) Å,c= 17.109(1) Å, β = 125.31(1) °,D m = 1.254,D c = 1.259 gcm−3 andZ= 2. Intensities were obtained from θ–2θ scans with a Syntex automated diffractometer using graphite-monochromated MoKα radiation. The structure was solved by direct methods. Full-matrix least-squares refinement of all positional and thermal (anisotropic for the nonhydrogen atoms and isotropic for the hydrogen atoms) parameters using 2022 reflections [I〉2σ(itI)] converged at a conventionalR of 0.041. The molecule is characterized by a conjugated pi system which includes the central N=C−C=N moiety and two of the four aniline groups. No intermolecular and only weak intramolecular hydrogen bonds are present.
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    Journal of chemical crystallography 5 (1975), S. 305-316 
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    Notes: Abstract The title compound, C16H24O4S3, crystallizes in the monoclinic system:a= 7.933(9) Å,b= 10.965(12) Å,c= 11.294(13) Å, β = 105.54(6) °,Z = 2, space groupP21 orP21/m. The structure could not be solved by direct methods in the former space group and was found to be disordered inP21/m with the molecule and its image mirrored aty= 1/4,3/4 occupying the same lattice site with occupancy 0.5.The manner in which molecular conflicts can be avoided in theP21/m structure is discussed. The molecular structure proposed by Praefcke et al. (1973) was confirmed.
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    Journal of chemical crystallography 5 (1975), S. 317-328 
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    Notes: Abstract The crystal structure of D-alloisoleucine has been determined using three-dimensional photographic data. The crystals are monoclinic:P21,Z= 4,a= 9.76 °,b= 5.33 Å,c=14.26 Å and β = 98.6 °. The structure was solved by packing considerations on the basis of the structure of L-isoleucine and refined by full-matrix least-squares, including anisotropic thermal parameters for all nonhydrogen atoms, to anR-factor of 0.118 for 1057 observed reflections. The two molecules in the asymmetric unit have different conformations as in the case of L-isoleucine.
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    Journal of chemical crystallography 5 (1975), S. 353-357 
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    Journal of chemical crystallography 5 (1975), S. 329-344 
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    Notes: Abstract The title compound, Cu(C10H24N4)(ClO4)2, crystallizes in the triclinic system with unit cell dimensionsa= 8.744,b= 8.022,c= 8.677 Å, α = 118.7, β = 56.9, γ = 113.5 °,Z= 1, space group P¯1. The structure was solved by Fourier methods and refined by least-squares techniques using the 1545 nonzero three-dimensional counter-diffraction intensity data (CuKα) to give a conventionalR factor of 0.056. The coordination sphere of the copper ion is defined by a planar arrangement of the four nitrogen donors in the macrocyclic ligand with oxygen atoms from the perchlorate groups lying above and below this plane. The resulting tetragonally distorted octahedron of donor atoms gives interatomic distances Cu−N = 2.02(4) Å and 2.02(3) Å, and Cu−N = 2.57(4) Å.
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    Journal of chemical crystallography 5 (1975), S. 377-385 
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    Notes: Abstract Crystals of hydridodinitratobis(triphenylphosphine) iridium(III), IrH(NO3)2(PPh3)2, belong to the trigonal system, space groupP¯3e1, with hexagonal unit-cell dimensionsa = 16.33(1),c = 22.85(2) Å, andZ = 6. The six Ir atoms lie in special positions. Two (of molecule 1) have site symmetry 32 and four (of molecule 2) have site symmetry 3. Both types of molecule have trigonal bipyramidal coordination with phosphorus atoms axial but do not have sufficient nitrate groups (two instead of three) to satisfy the site symmetry. Thus both types of molecule have disordered nitrate groups and the mode of coordination appears to be somewhat different at the two sites.
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    Journal of chemical crystallography 5 (1975), S. 359-376 
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    Notes: Abstract The crystal and molecular structure of (—)-menthyl-p-bromophenylglyoxylate has been studied by x-ray diffraction techniques using diffractometer data. Crystals of this compound are triclinic:a= 10.152(3),b=19.661(3),c = 9.220(3) Å, α = 92.45(2), β = 102.74(4), γ = 93.11(4) °, andZ = 4. The structure was refined by least squares toR = 0.064. All 88 hydrogen atoms were determined from electron density difference maps. The significant structural features are the following: (i) the four molecules are conformationally different from one another; (ii) the two 〉 C=O groups of the glyoxylate are twisted with respect to each other across the central C-C bond by angles ranging from 92 ° to 111 °; (iii) the phenyl group is coplanar with the proximal 〉 C=O group; and (iv) all four molecules exhibit a conformation in which the axial hydrogens on the cyclohexane rings eclipse the closer keto oxygen. The absolute configuration was determined by the anomalous dispersion method and is (1R, 3R, 4S).
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    Journal of chemical crystallography 5 (1975), S. 403-411 
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    Notes: Abstract 4-Amino-4-carboxylthiapyran crystallizes in space groupP21/c witha = 10.61,b = 6.55,c= 10.97 Å, β =96.3 °, andZ = 4. The structure was solved by the heavy-atom method, with 897 observed reflections, and refined to anR of 0.093. The packing of the structure is found to be very similar to that in the structure of 1-aminocyclohexane carboxylic acid. The conformation of the thiapyran ring exists in the “puckered chair” form.
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  • 44
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    Notes: Abstract The crystal and molecular structure of C39H66INO13 · CH3OH has been determined by single-crystal x-ray diffraction analysis. The compound crystallizes in the monoclinic space, groupP21, witha =14.35(1),b=14.38(1),c =10.91(1) Å, β = 96.10(5) °, andZ = 2. Three-dimensional intensity data were collected on a four-circle fully automated diffractometer. The structure was solved by the heavy-atom method. The positions of all atoms have been refined by block-diagonal and full-matrix least squares, using anisotropic temperature factors. The finalR value was 0.109 for 2194 independent reflections. The analysis does not confirm the hypothetical structure proposed by the Eli Lilly group, as far as a position of a cyclic carbonate moiety is concerned. They postulated that the cyclic carbonate moiety was attached to C(9) and C(11) of the erythronolide. The results obtained by us show that the cyclic carbonate moiety is attached to C(11) and C(12). The absolute configuration of the asymmetric centers agrees fully with that established for erythromycinA.
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  • 46
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    Notes: Abstract The crystal structure of the compound Mo2 VI O4 (2,2-dimethylpropane-1,3-diolate)2 · (H2O)2 has been determined. Crystals are triclinic, space groupP¯1 witha = 7.603(3),b = 6.396(3),c = 8.930(6) Å, α = 84.41(3) β = 94.92(3), γ =103.21(3) °, andZ = l. X-ray data were collected by counter methods using MoKα radiation, and least-squares refinement led toR = 0.028 for the 1346 independent reflections for which ¦F 0¦2 〉 3σ(¦F 0¦2). The dimeric complex possesses a centre of inversion, the molybdenum atoms being bridged by two oxygen atoms which form part of the two chelate rings present. The distorted octahedral environment of each molybdenum atom is made up of the two oxygen atoms of thecis-dioxo molybdenum group, two oxygen atoms, one bridging, from one chelating diol, a bridging oxygen atom part of the chelate of the neighboring molybdenum atom, and a water molecule. Mo-O distances range from 1.68 (within MoO2 group) to 2.31 Å (to water molecule) and the Mo ... Mo distance is 3.45 Å.
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  • 47
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    Notes: Abstract The crystal structure of ammonium [cis-dioxo(uramil-N, N-diacetato) molybdate(VI] monohydrate, C8H12MoN4O10, has been determined. The crystals are monoclinic: space groupP21/c,a = 6.744(3),b = 18.07(1),c = 11.500(9) Å, β = 102.01(5) °,Z = 4. X-ray data were collected by counter methods using MoKα radiation, and least-squares refinement led toR = 0.048 for the 1601 independent reflections for which ¦F 0 ¦2 〉 3σ(¦F α¦2). The anion contains acis-dioxo metal system while the ligand coordinates as a tetradentate through the nitrogen and two oxygen atoms of theN-diacetate group and a carbonyl oxygen atom of the uramil skeleton. Metal ligand bondstrans to the terminal oxygen atoms are significantly lengthened. The pyrimidine ring of the ligand having lost a proton from the C5 atom is planar and is also coplanar with the metal dioxo group.
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    Notes: Abstract The crystal structure of trispotassium [cis-trioxo(nitrilotriacetato)molybdate (VI)] monohydrate, C6H8K3MoNO10, has been determined. The crystals are monoclinic, space groupP21/c,a = 9.700(4),b = 19.628(6),c = 7.608(2) Å, β = 110.58(4) ° andZ = 4. X-ray data were collected by counter methods using MoKα. radiation, and least-squares refinement led toR = 0.055 for the 2234 independent reflections for which ¦F 0¦2 〉 σ(¦F 0¦2). The anion contains acis-trioxo metal system, while the ligand coordinates as a tridentate through its nitrogen atom and two of the three carboxylate oxygen atoms, the Mo atom being in a distorted octahedral environment. The two glycinato rings involved in the coordination are mutuallycis. The mean Mo-O (terminal) bond length is 1.74 Å and the lengths of the metal-ligand bonds are Mo-O 2.18, 2,25 Å; Mo-N 2.39 Å.
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    Journal of chemical crystallography 6 (1976), S. 23-29 
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    Notes: Abstract The structure of monohydrated 8-quinolinol-7-sulfonic acid has been determined from 1156 x-ray intensities obtained by counter methods at room temperature and refined by full-matrix least squares toR = 0.054. The space group isP21/c and the cell constants area = 7.08(1),b = 9.485(10),c = 16.407(10) Å,β = 115.5(5) °. The zwitterionic compound occurs in infinite sheets connected by hydrogen bonds through water of crystallization. Comparison of the bond parameters with those in a metal chelate reveals the effects of chelation on the molecular structure.
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    Journal of chemical crystallography 6 (1976), S. 43-53 
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    Notes: Abstract IR and Raman spectra are reported for polycrystalline samples of the isomorphousMNCO (M=K,Rb,Cs). The lattice modes are generally assignable to the symmetry species of the factor groupD 4h by analogy with those ofMN3, but the internal modes are not, in general, interpretable by any known practical analysis. These spectral features may be associated with the disorder of the NCO− ions in the crystal structure.
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    Journal of chemical crystallography 6 (1976), S. 31-42 
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    Notes: Abstract X-ray study of enhydrin bromohydrin, C23H29BrO10, reveals that the crystal has space groupP212121 with cell parametersa =10.08,b = 26.97, andc = 8.94 Å. There are four molecules in the unit cell. The structure was solved by direct methods, with three-dimensional CuKα diffractometer data to θ = 75 °, and refined by block-diagonal least squares to anR index of 11.4% for 2254 reflections. The molecule is a germacronolide sesquiterpene having acis sterochemistry at the C(1), C(10) double bond and atrans configuration at the epoxide ring, C(4)-O-C(5). The absolute configuration established on the basis of the anomalous scattering of CuKα. radiation by the bromine atom shows that the asymmetric atoms have the 4R, 5R, 6S, 7S, 8S, 9S, 20S, and 22S configurations.
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    Journal of chemical crystallography 6 (1976), S. 59-64 
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    Journal of chemical crystallography 6 (1976), S. 65-70 
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    Journal of chemical crystallography 6 (1976), S. 71-72 
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    Journal of chemical crystallography 6 (1976), S. 73-85 
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    Notes: Abstract The product of the reaction of (π-C5 H5)Ru(PPh3)2 Cl and CuC2Ph has been characterized by single-crystal x-ray diffraction techniques and shown to have stoichiometry (π-C5 H5)Ru(PPh3)2Cu(C2Ph)Cl-(CH3)2CO(I). The compound contains a phenylethynyl group σ-bonded to the ruthenium atom and simultaneously π-bonded to a terminal Cu-Cl bond. Crystals of this compound from acetone are monoclinic,P21/c, witha = 12.914, = 22.111,c = 16.534 Å, β = 110.77 °, andZ — 4. Full-matrix least-squares refinement constraining the phenyl rings of the triphenylphosphines, the cyclopentadienyl ring, and the solvent of crystallization (acetone) as rigid groups yieldedR and weightedR values of 0.084 and 0.075, respectively.
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    Journal of chemical crystallography 6 (1976), S. 101-111 
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    Notes: Abstract The title compound crystallizes in space groupP21, with unit cell parametersa = 9.777(1),b = 7.750(1),c= 15.884(2) Å, and β = 100.3 °;D c = 1.34 andD m = 1.33 g cm−3 andZ = 2. The structure was solved by direct methods and refined by block-diagonal least-squares procedures with weightedF values to a finalR w of 0.079 (R = 0.084). A total of 2243 intensities was measured, using a diffractometer and monochromated MoKα radiation, of which 826 were ⩽2σ(I) and classed as “unobserved.” In the crystal, the C(10) aryl group is approximately perpendicular to the tetrahydronaphthalene nucleus. The carbon atoms in each of the two sets ofortho-methoxyl groups are in opposition to each other and coplanar with their respective aromatic rings. The methoxyl group attached to the sulfur has an unexplained anomalously short C-O bond length, but otherwise bond lengths and angles are normal.
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  • 58
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    Notes: Abstract The crystal structure of 1,3-dinitro-4,6-di[3-(2,2,5,5-tetramethyl)pyrrolidinyl-N-oxide] aminobenzene monohydrate has been determined by single-crystal X-ray diffraction methods using the 1793 unique reflections for which 3 ° 〈 2θ 〈 40 ° andI 〉 3σ(I), and refined to a conventionalR index of 0.032. Counter methods using MoKα radiation were employed. Crystals form in the triclinic space groupP¯1 (No. 2) witha = 16.160(10),b = 11.686(6),c = 7.211(5) Å, α = 95.87(5) °, β = 98.67(5) °, and γ = 107.74(4) °. All hydrogen atom positions were determined. Intramolecular hydrogen-bonding between the nitro and amino groups has, in part, caused the central 20 atoms of the molecule, counting hydrogen atoms, to lie in an approximate plane. The benzene ring is distorted by its substituents to the symmetrymm2(C 2v ). The internal angles of the benzene ring range from 116.1 ° to 124.7 ° (esd = 0.3 °), and its bonds are between 1.368 Å and 1.436 Å (esd = 0.004 Å) in length. Four of the five atoms in each pyrrolidine ring are nearly coplanar; the remaining atom, the carbon bonded to the amine nitrogen in each case, lies approximately 0.53 Å from the corresponding plane. The best four-atom planes of the two pyrrolidine rings are each near to perpendicular to the central plane, giving the molecule a lobster-like appearance; they are each rotated approximately 15 °, in opposite senses, from perpendicular. The intramolecular distance between the two pyrrolidine nitrogen atoms, to which the unpaired charges can be assigned, is 7.68 Å. One of the nitroso oxygen atoms is hydrogen-bonded by two symmetry-equivalent water molecules. The inversion center necessitates that the remaining hydrogen atoms of these water molecules both hydrogen-bond to a symmetry-equivalent nitroso oxygen atom to give a hydrogen-bonded four-oxygen ring.
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    Journal of chemical crystallography 6 (1976), S. 113-123 
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    Notes: Abstract The crystals of the title compound are triclinic, with unit-cell dimensionsa =14.804(7),b =18.657(9),c = 22.955(13) Å, α = 90.2(1), β 106.6(1), γ = 91.0(1) °, space groupP¯1, andZ = 4. The crystal structure has been determined from x-ray diffractometer data by direct methods and Fourier techniques, and refined by least-squares methods using 11,383 independent reflections (I〉 2σ(I)) to anR value of 0.076. The structure consists of complex molecules with two distorted octahedra sharing a face. The first of the bismuth atoms is coordinated by six iodine atoms, three of them bridging, and the second by three bridging iodine atoms and three oxygen atoms of the triphenylarsinoxides. The orientation of the phenyl rings is the only significant difference between the two complex molecules in the asymmetric unit.
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    Journal of chemical crystallography 6 (1976), S. 125-137 
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    Notes: Abstract An alkaloid, C20H35N3, mp 113–114 ° C, isolated fromHovea linearis R. Br., was shown to be an optically active 16-epiormosanine, [α]D = 0.0 ° in ethanol. It crystallizes in the orthorhombic space groupP212121, with unit cell dimensionsa = 11.939(1),b = 14.143(1),c = 22.310(2) Å,Z = 8, and the two molecules in the asymmetric unit are of the same chirality. The x-ray crystal structure was solved by direct methods and refined, using difference and least-squares procedures, with 2516 intensities (I 〉 3σ I ) measured with CuKα radiation on a single-crystal diffractometer. The final refinement of the fractional coordinates and isotropic thermal parameters of the nonhydrogen atoms, with all the hydrogens included, yielded anR index of 0.082. The molecule of 16-epiormosanine resembles the related alkaloid podopetaline in the conformation of the fused ring system.
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    Journal of chemical crystallography 6 (1976), S. 153-168 
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    Notes: Abstract The structure of (±)-4,9,10-triacetoxy-2-methoxydibenzo[ce] oxepin-5-one (DHAT) has been determined by x-ray crystallographic methods. The crystals are monoclinic:a = 17.829(2),b = 7.937(1),c = 13.937(2) Å, β = 95.629(2) °, andZ = 4. The structure was solved by direct methods and refined by Fourier and least-squares techniques on 2862 symmetry-independent ¦F 0¦ data toR = 3.9%. A novel expansion of the pyrone ring of the parent compound has been found. There is no evidence for hydrogen bonding and there are no unusual intermolecular contacts.
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    Journal of chemical crystallography 6 (1976), S. 169-176 
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    Notes: Abstract The crystal structure of the 4-methylpyridine adduct of bis[1-(2-thienyl)-4, 4,4-trifluoro-1,3-butanedionatolnickel(II) was determined by a three-dimensional x-ray analysis using counter data. The crystals are monoclinic,C2/c, witha = 9.330,b = 18.278,c = 17.855 Å, and β = 95.1°. The structure was refined by full-matrix least squares toR = 0.10. The molecule has a two-fold axis, and both enantiomers withcis configuration occur in the crystal. The solvation by 4-methylpyridine is shown to weaken the chelate bonds in the same way as doestrans hydration.
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    Journal of chemical crystallography 6 (1976), S. 177-203 
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    Notes: Abstract The crystal structure of a monoclinic mercury oxychloride of composition Hg3 O2 Cl2 has been described. A crystallographically different mercury oxychloride of the same composition was reported. The crystal structure of this second modification, called the β-form, has been established through a single-crystal x-ray diffraction study. The β-form is also monoclinic, with space groupP21/c andZ = 8. The unit-cell at 25 ° C hasa = 10.826(5),b = 9.310(4),c = 11.5 15(5) Å and β = 71.04(8) °. The density is calculated to be 8.53 g cm−3, that observed by displacement being 8.53(2) g cm−3. Diffraction data were obtained using the θ-2θ scanning mode on a Picker four-circle automatic diffractometer with CuKα radiation. This apparently unsuitable radiation was chosen in order to test rigorously an absorption correction procedure. The structure was refined toR 1 = 4.0% through conventional least-squares reduction basedF. The structure of β-Hg3 O2 Cl2 is found to be markedly different from that of the earlier-determined α-Hg3O2Cl2; distorted Hg4O tetrahedra are linked into a three-dimensional array, terminated at four locations within the cell by covalent Hg-Cl bonds.
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    Journal of chemical crystallography 6 (1976), S. 217-222 
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    Notes: Abstract The structure of 6-t-butyl-1,2-naphthoquinone-1-oxime was determined by direct methods by the use of MoKα diffractometer data and was refined toR = 0.12. The crystals are monoclinic:a = 8.32(1),b = 6.70(1),c = 11.14(1) Å, β = 101(1) °,Z = 2,P21/m. The molecule is crystallographically flat and lies in a mirror plane. Pronounced diffuse scattering on [010] oscillation photographs is caused by disorder in the orientation of thet-butyl group. The compound occurs in the oxime form, and not as a 1,2-nitroso naphthol.
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    Notes: Abstract Bis(2 — methoxy — 4 — nitrophenolato)N,N,N′,N′ — tetramethylethylenediamine copper(II) dihydrate crystallizes in the orthorhombic systema = 16.160,b = 18.538,c = 8.263 Å,Z = 4, space groupPbcn. The structure was determined by Fourier methods with CuKα diffractometer data, and refined by full-matrix least squares toR = 0.052 for 1585 observed reflexions. The molecules exhibit crystallographic two-fold symmetry with the diad axis passing through both the copper atom and the center of the carbon-carbon bond of the tetramethylethylenediamine moiety. Both the methoxy and phenolic oxygen atoms coordinate to the metal, as does the nitrogen atom of the tetramethylethylenediamine group, giving the copper atom sixfold coordination. The oxygen atoms of a phenolic group and one nitro group are involved in hydrogen bonds with the water molecules, resulting in a pairing of molecules about centers of symmetry. The solid-state electronic reflectance spectrum of the compound indicates a Type 1 molecule (Bullock et al., 1974), and this has been confirmed by the crystal structure analysis.
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    Notes: Abstract The crystal structure of 2,4-dinitronaphthyl-2′,6′-dimethylphenyl ether, C18H14N2O5, has been determined by three-dimensional x-ray methods, as part of a study of hindered aryl ethers. The crystals are monoclinic, space groupP21/c witha = 13.416(1),b = 8.479(1),c = 14.808(2) Å, β = 111.65(1) ° andZ = 4. The structure was solved by direct methods using program REL and was refined by full-matrix least squares to anR value of 0.050. The torsion angles that describe the diphenyl ether conformation are 60/22 ° for C2′-C1′-O1-C1/C1′-O1-C1-C2, respectively. The average torsion angles for other naphthalene phenyl ethers are 65/25 °. There are no hydrogen bonds in this structure.
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    Journal of chemical crystallography 6 (1976), S. 259-266 
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    Notes: Abstract The preferred binding sites of RNase-S to dioxouranium(VI) and platinum(II) has been determined by Wyckoff et al. (1967a,b, 1970), elaborating protein and of heavy-atom derivatives reported by Wyckoff and coworkers. The major sites are exposed at the surface of the protein molecule and are not directly involved in the biological properties; the coordination geometry of the groups bound to the metal ions have been examined in comparison with model compounds.
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    Journal of chemical crystallography 6 (1976), S. 235-258 
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    Notes: Abstract The crystal structure of tetrakisthiourea cobalt(II) nitrate monohydrate has been solved and refined by full-matrix least squares, including anisotropic temperature factors, to a finalR of 0.066. The structure is made up of discrete tetrakisthiourea Co(II) molecular ions and NO 3 − ions bound together by hydrogen bonds with water molecules as well as ionic and van der Waals interactions. The local configuration of the cobalt(II) and its four bonded nearest sulfur neighbors is that of a distorted tetrahedron with an average Co-S distance of 2.30 Å. Three of the Co-S bonds appear to be made with sulfur sp2 orbitals and lone pairs whereas the remaining Co-S bond involves the S-C π molecular orbital as the electron donor. The thiourea groups appear to be normal. Tetrakisthiourea cobalt(II) nitrate monohydrate: orthorhombic,Pbca,a = 33.704(8),b = 11.734(2),c = 10.253(2) Å,Z = 8,D m = 1.68(2),D e = 1.66 g cm−3.
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    Journal of chemical crystallography 6 (1976), S. 267-278 
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    Notes: Abstract The crystal structure of methyl-3,4-dideoxy-3-(salicylidenylamino)-α-d-erythro-pentopyranoside has been determined by vector verification and successive Fourier syntheses, and refined by full-matrix least-squares calculations toR o = 0.063 for 596 observed reflections. The crystals are orthorhombic, space groupP212121, witha = 10.781(2),b = 12.075(2),c = 10.008(1) Å, andZ = 4. All substituents to the pyranose ring aresyn-clinal with respect to corresponding bonds in the ring. The atoms in the salicylidenylamino moiety, including H(13), are coplanar within experimental error. This group includes a very weak intramolecular hydrogen bond with N(I)-O(13) = 2.585(9) Å, O(13)-H(13)-N(1) = 122 °.
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    Journal of chemical crystallography 6 (1976), S. 279-289 
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    Notes: Abstract The structure of triphenylselenonium chloride dihydrate has been determined by single-crystal X-ray diffraction techniques. Crystals of the compound C18H15Se+, Cl−, 2H2O are monoclinic, space groupC2/c, witha = 12.798(3),b = 13.802(1),c = 19.933(34) Å, β = 9.0.0(1) ° andZ = 8. The structure was refined by full-matrix least-squares methods from 1444 diffraotometer intensities to a conventionalR of 0.067 and a weightedR of 0.072. The structure consists of pairs of triphenylselenonium cations which are weakly joined through pairs of bridging chloride ions. The water molecules are clustered in groups of four, separated by the triphenylselenonium chloride dimers. The hydrogen atoms of the water could not be positioned unambiguously, but it appears that hydrogen bonds link the four water molecules and the chloride ions together.
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    Journal of chemical crystallography 6 (1976), S. 291-298 
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    Notes: Abstract The crystal structure of 1-hydroxy-2,3-dicarbomethoxy-1,3-cycloheptadiene has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the triclinic space groupP¯1, witha = 10.721(7),b = 8.628(6),c = 6.214(6) Å, α = 91.65(5), β = 83.14(5), γ = 81.66(5) °, andD c = 1.33 g cm−3 forZ = 2. The finalR factor for 1385 observed reflections is 0.058. The compound exists in the enolic configuration.
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    Journal of chemical crystallography 6 (1976), S. 311-316 
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    Notes: Abstract The crystal structure of chlorodifluoroacetamide has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP21/n witha = 7.401(6),b = 8.123(6),c = 8.431(6) Å, β = 104.48(5) °, andD = 1.52 gcm−3 forZ = 4. The finalR factor for 650 observed reflections is 0.059. The compound exists with a rotational disorder in the -CClF2 group about the C-C bond. The occupancy factors for the major and minor conformations are 0.74 and 0.24, respectively.
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  • 74
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    Notes: Abstract The infrared (200–3500 cm−1) and Raman (50–3500 cm−1) spectra of two isotopic species of tetramethylbiphosphine-bisborane, (CH3)4P2·2BH3 and (CH3)4P2·2BD3, in the solid state at low temperatures have been recorded. The spectra have been interpreted in detail on the basis ofC 2h molecular symmetry. The P-B stretching modes were assigned to bands at 599 and 567 cm−1 in the Raman and infrared spectra of the “light” compound, respectively. Only one P-P stretching mode was observed in the Raman spectra. The vibrational data appear to be consistent with the presence of only one conformer in the solid state, which is at variance with the conclusions from an X-ray study. Considerable splitting of the low-frequency bending modes was observed for both compounds; this splitting has been attributed to the factor group.
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    Journal of chemical crystallography 6 (1976), S. 321-322 
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    Journal of chemical crystallography 6 (1976), S. 317-320 
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    Notes: Abstract This communication presents a preliminary report on the crystal structure of this important nucleotide, involved in lecithin synthesis in animal tissues. The crystallographic data were recorded using a four-circle diffractometer with Cu-Kα x-radiation. Crystal data: orthorhombic, space groupP212121 (No. 19),Z = 4,a = 6.98 pm,b = 123.6 pm,c = 292.3 pm,U = 2.522 nm3. The structure was solved by means of a Patterson and electron-density maps and refined by several cycles of least-squares using isotropic temperature factors toR = 0.14. The torsion angles associated with the furanosyl ring are, in general, at the very extreme of the range commonly observed for C(2′) endopuckering (Altona and Sundaralingam, 1972); their values are ν1 = 319 °, ν2 = 47 °, ν3 = 326 °, ν4 = 13 °, ν5 = 18 °. The phase angle of pseudorotation, calculated from these values using the formula given by Altona and Sundaralingam (1972) is 139 °. This shows the ribose ring to be slightly nearer to the C(1′) exopuckering than the C(2′) endopuckering conformation, but remote from being a C(3′) endo-conformer. The sugar ring, in fact, is very close to being an idealized twist conformer. This is supported by a four-atom least-squares planes study, and is consistent with the high χ value of 237 ° (Sundaralingam, 1973). Backbone torsion angles associated with the structure are ψ = 57 °, ψ′ = 133 °, φ = 174 °, and ω = 291 °. ψ′ is some 7 ° less than the preferred minimum value for C(2′) endopuckering.
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    Journal of chemical crystallography 7 (1977), S. 1-10 
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    Notes: Abstract The methanol adduct of powerine [methyl 10,17-dihydroxy-(16β,17β,20α)-yohimban-16-carboxylate], C21H26N2O4. CH3 OH, crystallizes in the orthorhombic space groupP212121 (no. 19) with cell dimensionsa = 8.558(3),b = 14.162(7),c = 16.993(7) Å. The crystal and molecular structure has been determined by X-ray diffraction analysis and refined using full-matrix least squares methods to a reliability index,R, of 0.090 with 1139 observed (F⩾ 2.5σ F ) intensities. With the configuration at C15 arbitrarily assigned α those at the chiral centers C3-H, C16-CO2Me, C17-OH and C20-H are respectively α,β,β,α: theC-D ring junction istrans and that ofD-E iscis. All bond lengths and bond angles are normal.
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    Journal of chemical crystallography 7 (1977), S. 21-27 
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    Notes: Abstract l-3-(2-Acetamido-2-ethoxycarbonyl)ethylindole is monoclinic:a = 11.469(8),b = 8.088(6),c = 8.457(6) Å, β = 106.45(7) °,Z = 2,P21. The structure has been solved by direct methods with CuKα three-dimensional photographic data, and refined by full-matrix least squares toR = 0.097 for 1390 observed reflections. The structure is stabilized by intermolecular N-H...O hydrogen bonds. The indole ring of the molecule is planar within experimental error.
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    Journal of chemical crystallography 7 (1977), S. 11-20 
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    Notes: Abstract The crystal and molecular structure of tetrakis(N,N′-dimethylthiourea) platinum(II) chloride has been solved and refined by least-squares methods to a finalR of 0.052 from 4145 reflections measured by counter techniques. The crystals are triclinic:P¯1,a = 10.06(1),b = 10.19(2),c = 14.06(2) Å, α = 89.7(1), β = 101.4(1), γ = 90.1(1) °,Z = 2,D m = 1.76,D c = 1.605 g cm−3. The structure consists of discrete Pt[SC(NHCH3)2] 4 2+ and Cl− ions, linked by a network of NH...Cl hydrogen bonds. The dimethylthiourea groups are bonded to the metal through sulfur with Pt-S bonds of 2.305(2) and 2.321(2) Å. The PtS4 is almost square planar with 0.24 Å displacement of Pt from the best plane of the sulfur atoms. The entire cation has an approximateC 4 symmetry. The shortest Pt...Cl distance is 3.677(2) Å.
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    Journal of chemical crystallography 7 (1977), S. 41-48 
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    Notes: Abstract dl-Homocysteic acid (DLH), C4H9NO5S. Melting point 274–276 °C. Space group and cell dimensions:F2dd;as = 6.06(3),b = 20.19(7),c = 23.25(5) Å,Z = 16,Dx = 1.709 g cm−3,D c = 1.711 g cm−3. Prismatic crystals were grown from aqueous solution. FinalR = 0.047 on 539 observed reflections. The molecules are zwitterions bound in an intricate hydrogen-bonded arrangement of cross-linked double helices.
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    Journal of chemical crystallography 7 (1977), S. 29-40 
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    Notes: Abstract High-resolution spectroscopic data—Raman, infrared, and electronic—have been employed for the study of low-temperature, phase III, hexamethylbenzene and its associated λ-type phase transition. Phase III is trigonal, with point groupS 6 and one molecule per primitive unit cell, giving anS 6 site group, anS 6 molecular group, and a trivial interchange group. The λ-type phase transition is not second order, and it is not related to a free rotation of the methyl groups. Restricted, geared methyl-group rotations do exist both above and below the phase transition temperature, and are sensitive to it. The molecular point symmetry isS 6 in phase III and effectively so in phase II.
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    Journal of chemical crystallography 7 (1977), S. 59-67 
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    Notes: Abstract (−)-N,N-Dimethylamphetamine methiodide, C12H20N+,I− crystallizes in the monoclinic space groupP21 with unit-cell dimensionsa = 5.999(2),b = 8.330(3),c = 13.161(3) Å, β = 94.03(2) °, andZ = 2. The structure was solved by the heavy-atom method from CuKα. intensities visually estimated from Weissenberg films, but refined on data measured with MoKα radiation on a Rigaku-AFC four-circle diffractometer. Full-matrix least-squares refinement of the nonhydrogen atoms with anisotropic temperature factors, has yielded a finalR index of 0.045 for the 1124 observed terms. The absolute configuration has been defined by Bijvoet's technique.
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    Journal of chemical crystallography 7 (1977), S. 49-57 
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    Notes: Abstract Ovatifolin, C17H22O5, is a sesquiterpene lactone isolated from the aerial parts ofPodanthus mitiqui Lindl. (Compositae) collected near Pichidangui, Chile. Extracts of the plant exhibit cytotoxic activity against KB cell cultures. The pale yellow crystals belong to the orthorhombic space groupP212121 with cell dimensionsa = 8.159(1),b = 6.640(1), andc = 29.314(4) Å. Data were collected on an automatic diffractometer and the structure was solved by direct methods. The model was refined anisotropically to anR value of 0.047 using all 1742 measured intensities. The 10-memberedtrans-trans-germacradiene ring adopts a chair-chair conformation with C(4) and C(10) methyl groups orientedsyn on the β face of the molecule. The conformation leads to a crossed double-bond system in which transannular interactions shift the ultraviolet absorption to 210 nm. The five-membered lactone ring adopts a distorted chair conformation and istrans-fused to the 10-membered ring.
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    Journal of chemical crystallography 7 (1977), S. 69-79 
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    Notes: Abstract The structure of decahydroquinoline hydrobromide has been determined by the heavy-atom technique. This compound, C9H18NBr, crystallizes in the orthorhombic space groupPbcn (N ° 60), witha = 26.885(3),b = 9.952(1),c = 7.750(1) Å, andZ = 8. The structure was refined by block-diagonal least-squares methods to a finalR value of 0.086, including the hydrogen atoms located theoretically. Decahydroquinoline has a chair conformation. The molecules are held together by a network of hydrogen bonds of type N+−H...Br− along thec axis, and by van der Waals forces in the other directions. A comparative study with the structure of piperidine hydrobromide is given.
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    Journal of chemical crystallography 7 (1977), S. 81-93 
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    Notes: Abstract The title compound [Co(NH3)6] [Na(EDTA-4H)],3.5H2O has been synthesized, and its crystal structure has been determined from 2064 independent single-crystal reflections measured on a diffractometer. The crystals are tetragonal, space groupP4212, with unit-cell parametersa = 14.618(5) andc = 10.658(4) Å. There are four formula entities in the unit cell givingD c = 1.562(2) g cm−3 compared withD m = 1.56(1) g cm−3. The structure was solved by conventional Patterson and Fourier techniques, and refined by full-matrix least-squares methods to a final agreement factor of 3.6%. The compound contains two crystallographically independent octahedral [Co(NH3)6]3+ ions, with an average Co—N distance of 1.966(6) Å, and a seven-coordinate sodium ion which is coordinated to four carboxyl oxygens, two amine nitrogens, and a water molecule which bridges to another sodium ion. The EDTA is therefore acting in its normal hexadentate manner. The range of Na—O distances is 2.25 to 2.93 Å whereas the Na—N distance is 2.46 Å. The crystal structure is additionally stabilized by extensive hydrogen bonding among coordinated ammonias, carboxyl oxygens, and water molecules.
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    Notes: Abstract The crystal and molecular structure of 1,4-bis(p-chlorobenzoyl)-5-methylene-7-methyl-2,3,4,5-tetrahydro-1H-1,4-diazepine has been determined by X-ray methods. The crystals are triclinic,P¯1,a = 10.605,b = 13.054,c = 7.351 Å, α = 94.24, β = 101.53, γ = 101.55 °,Z = 2. The structure was solved by direct methods, and refined by full-matrix least squares toR = 5.6% on 3495 “observed” reflections. The structure is of the enamide form with diacylation on nitrogen. There are no abnormal bond lengths or intermolecular contacts.
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    Journal of chemical crystallography 7 (1977), S. 107-114 
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    Notes: Abstract Isopimpinellin (5,8-dimethoxypsoralen), C13H10O5, is a furanocoumarin isolated from the leaves and stems ofA pium australe Thouars. (Umbelliferae) collected near Concepción, Chile. Extracts of the plant show activity against P-388 lymphocytic leukemia. Isopimpinellin is a pale yellow crystalline compound belonging to the monoclinic space groupP21/n with cell dimensionsa = 17.561(3),b = 4.3682(5),c = 17.143 Å, and β = 122.97(1) °. Data were collected on an automatic diffractometer and the structure was solved by direct methods. The model was refined anisotropically to anR value of 0.046 using all 2123 measured reflections. The furanocoumarin system is nearly planar, with the lactone ring and the furan ring making angles of 1.8 ° with the central phenyl ring. The methoxyl methyl group at the heteroatom end of the molecule is out of the molecular plane whereas the otter methoxy methyl lies in the plane.
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    Notes: Abstract Crystals of the title compound are monoclinic,a = 13.966(4),b = 9.141(3),c= 15.901(6) Å, β=123.0(7) °,Z = 4. The structure was established by direct methods based on 2827 reflections, using MoKα radiation, refined to an ultimate coventionalR of 0.081. The furanone ring is closely similar to that found in a related spiro-connected molecule in this series.
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    Journal of chemical crystallography 7 (1977), S. 123-135 
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    Notes: Abstract Ethylenediamine-(+)-tartrate (EDT), C2N2H 10 2+ .C4O6H 4 2− , crystallizes in the monoclinic system:a = 8.986(3),b = 8.807(3),c = 5.977(2) Å, β = 105.62 °(1),Z = 2,P21. The structure has been determined by a combination of vector verification and partial electron density syntheses using CuKα photographic data, and refined by full-matrix least squares toR o = 0.035 andR w = 0.047 with CuK α diffractometer data for 904 observed reflections. Both nitrogen atoms of the ethylenediamine group are protonated, giving rise to two cationic centers, while the carboxylate groups of the tartrate moieties are anionic. There are eight intermolecular hydrogen bonds in the asymmetric unit, and one weak intramolecular hydrogen bond in the tartrate group.
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    Journal of chemical crystallography 7 (1977), S. 147-155 
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    Notes: Abstract An x-ray analysis of two natural compounds isolated fromPiper sanctum confirmed thetrans configuration for 5-(8-methoxy)cinnamyliden-4-methoxy-but-3-enolide [piperolide (I)] and for 5-[trans-(z)-β,γ-epoxy-α-methoxycinnamyliden]-4-methoxy-2(5H)-furanon [epoxypiperolide (II)]. The space groups arePbca [a = 44.174(3),b = 8.056(3),c = 7.515(4) Å] for (I) andP21/c [a = 11.351(4),b = 8.292(5),c = 14.292(2) Å, β = 96.28(2) °] for (II). The structures were solved by direct methods and refined by least-squares techniques toR = 4.8% (I) andR = 7.5% (II). The stereochemistry of the semicyclic double bond is in favor of theZ-isomers.
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    Journal of chemical crystallography 7 (1977), S. 137-146 
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    Notes: Abstract The crystal and molecular structure of bis[(1,2-dihapto-3,5-dimethylpyrazolido)-π-allylpalladium(II)], C16H24N4Pd2, has been determined by X-ray diffraction techniques. The crystals are monoclinic,P21/c (No. 14), witha = 8.752(1),b = 18.932(2),c = 11.780(3) Å, and β = 109.78(1) °. The observed crystal density (1.746 g cm−3) agrees well with that calculated on the basis of four molecules per unit cell (1.754 g cm−3). The structure has been refined by full-matrix least-squares techniques to a finalR 1 value of 0.045 (R 2 = 0.056) for 2974 unique reflections withI net⩾7 counts sec−1. The Pd2N4 ring is in a boat conformation in which the two palladium atoms are 1.113 and 1.064 Å out of the plane defined by the four nitrogen atoms. The Pd-C bond distances to the terminal atoms of the π-allyl groups (2.12 Å) are longer than those to the central carbon atoms (2.06 Å). The molecule possesses approximatemm2 (C 2v ) symmetry.
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    Journal of chemical crystallography 7 (1977), S. 157-159 
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    Journal of chemical crystallography 7 (1977), S. 161-171 
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    Notes: Abstract The crystal and molecular structure of 2,7-anhydro-l-glycero-β-d-manno-octulopyranose has been determined by X-ray analysis. Crystal data area = 9.590(4),b = 7.404(5),c=7.363(4) Å, β = 101.79(3)°,Z = 2, space groupP21. The phase problem was solved by direct methods, using diffractometer data, and the structure was refined by least-squares techniques to a finalR value of 3.7%. The anhydro ring system is built up by the pyranosyl chair in the1 C 4 conformation, the five-membered ring in theE 0 conformation, and a boat-shaped seven-membered ring. Potential energy calculations show that the positions of the terminal CH2OH groups are determined by hydrogen bonds.
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  • 94
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    Journal of chemical crystallography 7 (1977), S. 189-197 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of copper bis(tenuazonate) monohydrate has been determined by X-ray diffraction from 968 counter-measured intensities. The thin flat crystals are monoclinic,P21, witha = 13.77(1),b = 15.51(1),c = 11.14(1) Å, β = 109.5(2) °, and two formula units, C20H26CuN2O6·H2O, per asymmetric unit. The structure was refined by full-matrix least squares toR = 0.056. Because of the dimerization one copper ion is four- and the other five-coordinate. The dimers are hydrogenbonded into sheets by water molecules.
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  • 95
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    Journal of chemical crystallography 7 (1977), S. 173-182 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of bis(quinoxaline)-2,2′3,3′-disulfide, C16H8N4S2, was determined by direct methods and refined by least-squares methods, using 823 reflections collected with a two-circle Weissenberg diffractometer, including anisotropic temperature factors for nonhydrogen atoms to a finalR of 0.104. The crystals are monoclinic prismatic: space groupP21/a,a = 18.98(2),b = 9.27(2),c = 3.89(1) Å, β = 100.3 °(1),Z = 2. The structure consists of layers of molecules staggered along thec axis. The molecule is centrosymmetric, and makes an acute angle of 36.9 ° with theab plane; it is planar within an rms atom deviation of 0.02 Å. The S-C (1.752–1.760 Å) distances are normal for a S-C (sp2) bond. The N-C bonds (1.372–1.381 Å) adjacent to the benzene ring are longer than the N-C bonds (1.318–1.322 Å) adjacent to the central C4S2 ring.
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  • 96
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The title compound (C6H8N)2Mo2I6(H2O)2 crystallizes in theP¯1 space group, witha = 8.127(3),b = 8.337(3),c = 10.415(4) Å, α = 73.99(2), β = 84.35(2), γ = 73.91(2) ° andZ = 1. The structure was solved by direct methods and refined to the unweighted and weighted residuals of 0.044 and 0.052. The structure is characterized by the eclipsed configuration of the iodide ions and water molecules within Mo2I6(H2O) 2 2− ion and very short Mo-Mo bond distance 2.115(1) Å. Three independent Mo-I distances are 2.784(1), 2.760(2) and 2.797(1) Å. 4-Methylpyridinium ion is planar within 0.02° Å. The compound is isostructural with (C6H8N)2Mo2Br6(H2O)2.
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  • 97
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    Journal of chemical crystallography 7 (1977), S. 199-205 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
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  • 98
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    Journal of chemical crystallography 7 (1977), S. 207-209 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
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  • 99
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    Journal of chemical crystallography 7 (1977), S. 211-218 
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Crystals of the title compound, C17H16BrNO, are monoclinic, space groupP21/n, unit-cell parametersa = 14.48,b = 6.20,c = 16.72 Å, and β = 97.35 °. Three-dimensional data were collected with CuKα radiation using an automatic diffractometer. The structure was solved by the heavy-atom method and refined by block diagonal least squares to anR index of 0.088 for 2210 reflections. The main features obtained from our studies are (i) the C=O group is orientedanti to the benzene ring, in agreement with the nmr studies; (ii) the C(2) proton is equatorial while the methyl group at C(2) is in an axial position, also in agreement with nmr data. The bromobenzoyl ring and the benzene ring are at 64 ° to each other, while the carbonyl 〉C=O and the bromobenzoyl groups Br are at 42 ° to each other.
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  • 100
    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structures of the naturally occurring, N(3)-substituted purine triacanthine (6-amino-3-dimethylallylpurine) are presented. Triacanthine crystallizes, from a saturated DMSO solution, in the monoclinic system, space groupP21/c. Crystallographic data are as follows:a = 12.451(4),b = 8.508(4),c = 11.365(3) Å, β = 122.74(2) °,V c = 1012.66 Å3,Z = 4,D m = 1.335(1),D x = 1.333 g cm−3. The structural solution was obtained by direct methods and has been refined, based on full-matrix least squares with 2124 observedF o data, to a finalR value of 0.075. The principal molecular features are (1) the occurrence of the substituted purine as the amino tautomer, (2) a nearly planar purine ring system, and (3) a highly planar dimethylallyl group oriented approximately orthogonally to the purine ring system. The crystal packing is dominated by intermolecular hydrogen bonds involving the exocyclic amino group and the acceptor sites N(1) and N(9). Sheets of such hydrogen-bonded molecules are stacked along [10¯1]. Two distinct types of molecular overlaps are observed within these stacks.
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