ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Evolution structurale de la nacrite en fonction de la nature des molécules organiques intercalees (2000)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 33 (2000), S. 1351-1359 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Nacrite has been intercalated with two polar organic molecules: dimethyl sulfoxide (DMSO) and N-methylacetamide (NMA). The homogeneous nacrite complexes have been studied by X-ray diffraction (XRD) and infrared (IR) spectroscopy. The XRD study is based on a comparison between experimental and calculated patterns. The structures of the intercalated compounds have been determined, including the mutual positions of the layers after intercalation and the positions of the intercalated molecules in the interlayer space. It has been shown that the intercalation process causes not only a swelling of the interlayer space but also a shift in the mutual in-plane positions of the layers. This shift depends on the nature of the intercalated molecules and is related to their shape and the hydrogen bonds which are established with the surrounding surfaces. For a given molecule, the intercalation process is the same for the different polytypes of the kaolinite family. These XRD results are consistent with those of IR spectroscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889800011730
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Etude structurale d'un hydrate 10 Å instable de kaolinite (2000)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 33 (2000), S. 1075-1081 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The treatment of KGa-1 kaolinite with dimethyl sulfoxide and ammonium fluoride heated at 383 K provides an unstable hydrated phase characterized by a 10 Å basal distance. When air-dried, this hydrate gives a dehydrated phase at 7.15 Å. The aim of this work is to determine the structural characteristics of this hydrate. The method used to characterize this hydrate is based on the comparison between experimental and calculated X-ray diffraction profiles. This study is achieved in two steps: the study of 00l reflections enabled the determination of the number of intercalated water molecules, their positions and the stacking mode along the normal to the (a, b) plane; and the study of the hkl reflections with h and/or k ≠ 0 enabled the determination of the stacking mode and the positions of water molecules in the (a, b) plane. The unstable hydrate is characterized by two water molecules per Al2Si2O5(OH)4 unit situated at z1 = z2 = 7.57 Å. Two adjacent layers are translated with respect to each other with TI = −0.155a + 0.13b + 10n.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889800004878
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Étude par Diffraction X des Modes d'Empilement de la Nacrite Hydratée et Deshydratée (1998)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 31 (1998), S. 654-662 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: X-ray diffraction based on the comparison of experimental and calculated powder profiles enabled the determination of the structural characteristics of hydrated and dehydrated Tunisian nacrite. Using the concept describing the structure of natural nacrite, the stacking mode of the layers in the hydrated and dehydrated nacrite has been determined. The hydrate is characterized by an 8.42 Å basal distance; one water molecule per Si2Al2O5(OH)4 is intercalated in the interlamellar space, located above the vacant octahedral site of the layer at z = 6.5 Å and inserted inside the ditrigonal cavity of the tetrahedral sheet of the upper layer. The dehydrated nacrite obtained by heating of the hydrate at 423 K has the same interlayer shift t = −0.35a as the natural nacrite. Coherence domain sizes along c^{\ast} and in the ab plane are the same as those in the hydrate but different from those of the natural mineral. After dehydration, 5% of the layers had an interlayer shift similar to that obtained from the hydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889898000363
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Etude structurale par diffraction des RX et spectroscopie IR des hydrates 10 et 8.4 Å de kaolinite (1999)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 32 (1999), S. 968-976 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Two hydrated kaolinites, characterized by 10 and 8.4 Å basal distances, were synthesized by treating the kaolinite KGa-1 with dimethyl sulfoxide (DMSO) and ammonium fluoride (NH4F). The X-ray diffraction study was based on a comparison between the experimental and calculated profiles. This study was conducted in two steps: firstly, the study of the 00l reflections enabled the determination of the stacking mode along c*, the number of water molecules and their positions along the normal to the plane of the sheet structure; secondly, the study of the hk bands, with h and/or k ≠ 0, enabled the determination of the stacking mode and the positions of the water molecules in the (a,b) plane. The 10 Å hydrated kaolinite is characterized by two water molecules per Al2Si2O5(OH)4 unit, situated at 3 and 3.4 Å from the hydroxyl surface, over the octahedral sites. Two adjacent layers are translated with respect to each other, with T11 = −0.38a − 0.37b + 10n. The 8.4 Å hydrated kaolinite is characterized by one water molecule per Al2Si2O5(OH)4 unit, situated at 2.4 Å from the hydroxyl surface and inserted between the vacant octahedral site and the ditrigonal cavity of the tetrahedral sheet. The corresponding interlayer shift is T11 = −0.355a + 0.35b + 8.4n.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889899008602
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Étude Structurale d'une Nacrite Tunisienne (1997)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 30 (1997), S. 338-344 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: X-ray diffraction based on the comparison between the experimental and the calculated (20,11) and (02,31) powder profiles enabled determination of the structural characteristics of a Tunisian nacrite. The nacrite has space group Cc and the stacking mode is 2M. The two-layer periodicity could be described by a rotation of adjacent layers by 60° with the same interlayer shift between all layers (t = −0.35a along the 8.9 Å axis). Because the 60° rotated layer can be deduced from the nonrotated one by a mirror plane parallel to the 8.9 Å axis, the nacrite can also be described by the stacking of two symmetric layers. This better explains the unique translation between layers and is coherent with the previous description of stacking faults in the other members of the kaolinite family, i.e. kaolinite and dickite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889896014318
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...