Investigation of the CsxRb1-xTiOAsO4 series. I. Crystal structure analysis and pseudosymmetry
UNSPECIFIED. (1998) Investigation of the CsxRb1-xTiOAsO4 series. I. Crystal structure analysis and pseudosymmetry. ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 54 (Part 5). pp. 635-644. ISSN 0108-7681Full text not available from this repository.
Refinements of five crystals in the Cs2xRb2-2x-Ti2O2As2O8 series, caesium rubidium titanyl arsenate, with x = 0.07, 0.31, 0.58, 0.71 and 0.86, which are compositional analogues of KTiOPO4 (KTP), have been completed at 293 K and two (x = 0.71, 0.86) at low temperature. All the structures are found to be orthorhombic (space group Pna2(1)) and are isostructural with KTP, although there is evidence of some Cs disorder over additional sites in the framework, particularly at the Cs-rich end of the series, as discussed in Part II [Thomas & Womersley (1998). Acta Cryst. B54, 645-651]. Unusually large U-33 parameters for shared Cs/Rb sites are observed and are shown to be the result of the existence of separate sites for Ca and Rb within the structural framework, although the coordinates of these sites cannot be resolved convincingly. The structural changes in the TiO6/AsO4 framework. required to accommodate an increasing fraction of the larger Cs cation across the series and under cooling to 120 K are elucidated. Finally, the deviations of the room-temperature and low-temperature structures from the high-temperature prototypic structure (space group Pnan) are examined and suggest that the phase-transition temperature should increase linearly from CsTiOAsO4 to RbTiOAsO4.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE|
|Publisher:||MUNKSGAARD INT PUBL LTD|
|Date:||1 October 1998|
|Number of Pages:||10|
|Page Range:||pp. 635-644|
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