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  • Chemistry  (5)
  • Sodium scandium fluoride
  • 1985-1989  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 523 (1985), S. 89-98 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of the Compounds BaCaGaF7 and BaCaCrF7The isostructural fluorides BaCaGaF7 and BaCaCrF7 (values in parentheses) crystallize monoclinically in space group P2/n, Z = 4: a = 539.0 (539.8), b = 541.0 (542.2), c = 1897.8 (1900.6) pm, β = 92.33 (92.10)°. Complete X-ray single crystal structure determinations showed, that the compounds are built up from triple layers [CaF8/2 · MF3]2-, which consist of a central sheet of edge-sharing CaF8/22- polyhedra (distorted square antiprisms) with MIIIF6octahedra condensed on it at both sides and which are held together by 12-coordinated barium ions. The resulting average distances are: Ga—F = 187.8 (Cr—F = 189.4) pm, Ca — F = 236.2 (236.2) pm, Ba—F = 289.4 (289.4) pm. Some relations to the structures of other fluorides are discussed.
    Notes: Die isostrukturellen Fluoride BaCaGaF7 und BaCaCrF7 ( Werte in Klammern) kristallisieren monoklin in der Raumgruppe P2/n, Z = 4: a = 539,0 (539,8), b = 541,0 (542,2), c = 1897,8 (1900,6) pm, β = 92,33 (92,10)°. Vollständige röntgenographische Einkristallstrukturbestimmungen zeigten, daß sie aus Dreierschichten [CaF8/2 · MF3]2- aufgebaut sind, die aus einer zentralen Schicht kantenverknüpfter CaF8/22--Polyeder (verzerrte quadratische Antiprismen) mit beidseitig aufgesetzten MIIIF6-Oktaedern bestehen und durch Bariumionen in Zwölferkoordination zusammengehalten werden. Als mittlere Abstände resultierten: Ga—F = 187,8 (Cr—F = 189,4) pm, Ca—F = 236,2 (236,5) pm, Ba—F = 289,4 (289,4) pm, Beziehungen zu den Strukturen verwandter Fluoride werden diskutiert.
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  • 2
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetragonal Fluoroperovskites AM0,75 □ 0,25F3 Deficient in Cations: K4MnIIM2IIIF12 and Ba2Cs2Cu3F12By heating 2KMnF3 + K2MnF6 and BaF2, CsF + CuF2 respectively, the isostructural tetragonal compounds K4Mn3F12 (a = 832.2, c = 1643.0 pm) and Ba2Cs2Cu3F12 (a = 854.1, c = 1704.1 pm) were prepared. They crystallize in a cation-deficient perovskite structure exhibiting ordering of octahedral vacancies. Single crystal structures determinations in the space group I41/amd, Z = 4, yielded the following average distances within the octahedra, which are Jahn-Teller distorted for MnIII and CuII:MnII—F = 208.3 pm, MnIII—F = 4 × 183.0/2 × 209.7 pm; Cu—F = 190.7/227.1 and 190.6/236.4 pm, respectively. The results are discussed in comparison with related compounds.
    Notes: Durch Erhitzen von 2KMnF3 + K2MnF6 bzw. von BaF2, CsF und CuF2 wurden die isostrukturellen tetragonalen Verbindungen K4Mn3F12 (a = 832,2, c = 1643,0 pm) bzw. Ba2Cs2Cu3F12 (a = 854,1, c = 1704,1 pm) hergestellt. Sie kristallisieren in einer kationendefizitären Perowskitstruktur mit geordneter Verteilung der zu einem Viertel unbesetzten Oktaederlücken. Die Einkristallstrukturbestimmungen in der Raumgruppe I41/amd, Z = 4, ergaben folgende mittlere Abstände in den für MnIII and CuII Jahn-Teller-verzerrten Oktaedern: MnII - F = 208,3 pm, MnIII—F = 4 × 183,0/2 × 209,7 pm; Cu—F = 190,7/227,1 bzw. 190,6/236,4 pm. Die Resultate werden im Vergleich mit verwandten Verbindungen diskutiert.
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  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Usovites Ba2MIIM′IIM2IIIF14 and the High Pressure Phases of BaMnVF7 and BaMnFeF7: Compounds with BaMnGaF7 StructureThe results of complete single crystal structure determinations of the monoclinic BaMnGaF7 type compounds Ba2CaCoV2F14 (and Ba2CdMn Fe2F14) are reported: C2/c, Z = 4, a = 1369.7 (1381.2), b = 538.4 (537.2), c = 1491.6 (1489.5) pm, β = 91.49 (91.11)°, Rg = 0.036 (0.038) for 4389 (2521) reflections. The atoms Ca/Co (Cd/Mn) distribute not completely ordered on the 8- and 6-coordinated sites of this “usovite” structure (Ba2CaMgAl2F14). This is also evident for Cd/Fe from Mössbauer spectra of Ba2CdFeAl2F14. The lattice constants of this and further seven compounds Ba2MIIM′IIM2IIIF14 (MII = Ca, Cd; M′II = Mg, Mn—Cu; MII = Al, Ga) are given. Two novel representatives of the same structure with MII = M′II = Mn could be prepared in the form of the high pressure phases of BaMn VF7 and BaMnFeF7. The magnetic properties of both modifications of the iron compound and of BaMnGaF7 are reported and discussed.
    Notes: Die Ergebnisse vollständiger Einkristallstrukturbestimmungen an den monoklin im BaMnGaF7-Typ kristallisierenden Verbindungen Ba2CaCoV2F14 (und Ba2CdMnFe2F14), werden mitgeteilt: C2/c, Z = 4, a = 1369,7 (1381,2), b = 538,4 (537,2), c = 1491,6 (1489,5) pm, β = 91,49 (91,11)°, Rg = 0,036 (0,038) für 4389 (2521) Reflexe. Die Atome Ca/Co (Cd/Mn) sind nicht vollständig geordnet auf die 8- und 6fach koordinierten Plätze dieser “Usovitstruktur” (Ba2CaMgAl2F14) verteilt. Das zeigen auch Mößbauer-spektroskopische Untersuchungen für Cd/Fe in Ba2CdFeAl2F14. Die Gitterkonstanten dieser und weiterer sieben Fluoride Ba2MIIM′IIM2IIIF14 (MII = Ca,Cd; M′II = Mg, Mn—Cu; MIII = Al, Ga) werden angegeben. Zwei neue Vertreter derselben Struktur mit MII = M′II = Mn konnten in Form der Hochdruckphasen von BaMnVF7 und BaMnFeF7 dargestellt werden. Die magnetischen Eigenschaften beider Modifikationen der Eisenverbindung und von BamnGaF7 werden mitgetwilt und diskutiert.
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structures of Cesium-containing Fluorides. VIII. Cs7Ni4F15 and Cs7Co4F15: Crystal Structure Determination of the Hitherto Cesium-richest Compounds in the Corresponding Systems CsF/MF2.The only nickel-containing phase we could identify after solid state reaction 2 CsF + NiF2 was the compound Cs7Ni4F15. The single crystal structure determination of this monoclinic fluoride (and its cobalt analog Cs7Co4F15) yielded a = 787.2 (788.3), b = 1089.7 (1096.6), c = 1149.5 (1164.9) pm, β = 92.74 (92.59)°, space group P21/c, Z = 2, Rg = 0.045 (0.058) for 2543 (2716) independent reflections. The resulting strongly puckered layer structure rather than of single octahedra consists of face-sharing M2F9 units, which are connected via the half of their remaining corners. The M—F distances vary from 195.1 to 212.0 (196.7 to 217.0) pm and show unusual high mean values of 203.7 (206.5) pm. Data for comparison and further details are discussed.
    Notes: Als einzige nickelhaltige Phase bei der Festkörperreaktion 2 CsF + NiF2 konnten wir die Verbindung Cs7Ni4F15 identifizieren. Die Einkristallstrukturbestimmung an diesem monoklinen Fluorid (und der analogen Cobaltverbindung Cs7Co4F15) ergab: a = 787,2 (788,3), b = 1089,7 (1096,6), c = 1149,5 (1164,9) pm, β = 92,74 (92,59)°, Raumgruppe P21/c, Z = 2, Rg = 0,045 (0,058) für 2543 (2716) unabhängige Reflexe. Es liegt eine stark aufgerauhte Schichtstruktur vor, in der statt Einzeloktaedern nur flächenverknüpfte M2F9-Einheiten vorkommen, die über die Hälfte der verbleibenden Ecken miteinander verbunden sind. Die M—F-Abstände variieren von 195,1 bis 212,0 (196,7 bis 217,0) pm und sind im Mittel mit 203,7 (206,5) pm anomal groß. Vergleichsdaten und weitere Einzelheiten werden diskutiert.
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  • 5
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Single Crystal Structure Determinations of the Cubic High Pressure Elpasolites Rb2LiFeF6 and Cs2NaFeF6: Pressure-Distance Paradox without Change of Coordination NumberAt single crystals of metastable high pressure phases of Rb2LiFeF6 (a = 824.4 pm) and Cs2NaFeF6 (a = 873,9 pm) the parameters of the cubic elpasolite structure (Fm3m, Z = 4) were determined by X-ray methods. Compared to the 12L-structures of the normal pressure phases (R3m, hex. Z = 6) only the distances within the 12-coordination, Rb—F = 291.7 resp. Cs—F = 309.9 pm, are compressed by 2-3%. However, the octahedral distances Fe—F = 194.6 pm and Li—F = 217.6 pm resp. Fe—F = 194.9 pm and Na—F = 242.0 pm, are enlarged by 1-4%, though there was no increase in coordination number. This paradoxical behaviour is discussed. Difference Fourier syntheses reveal disorder only for the lithium positions in Rb2LiFeF6, which are 30 pm off-center, corresponding to a splitting of distances Li—F into 188, 247 and 4 × 220 pm.
    Notes: An Einkristallen der metastabilen Hochdruckphasen von Rb2LiFeF6 (a = 824,4 pm) und Cs2NaFeF6 (a = 873,9 pm) wurden röntgenographisch die Parameter der kubischen Elpasolithstruktur (Fm3m, Z = 4) bestimmt. Gegenüber den 12 L-Strukturen der Normaldruckphasen (R3m, hex. Z = 6) sind nur die Abstandswerte in der Zwölferkoordination, Rb—F = 291,7 bzw. Cs—F = 309,9 pm, um 2-3% verkleinert. Aber für die oktaedrischen Abstände Fe—F = 194,6 pm und Li—F = 217,6 pm bzw. Fe—F = 194,9 pm und Na—F = 242,0 pm ergeben sich Aufweitungen von 1-4%, obwohl keine Erhöhung der Koordinationszahl stattgefunden hat. Dieses paradoxe Verhalten wird diskutiert. Nur für die Lithiumpositionen in Rb2LiFeF6 zeigen Differenzfouriersynthesen eine Fehlordnung, die einer Li-Auslenkung von 30 pm aus dem Oktaederzentrum und einer Li—F-Abstandsaufspaltung in 188, 247 und 4 × 220 pm entspricht.
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