ISSN:
1063-7745
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract The characteristic structural features of a single crystal of the anion-excessive fluorite phase Ca0.88Gd0.12F2.12 have been studied by X-ray diffraction analysis (MoK α radiation), sp. gr. Fm3m, Z = 4, a = 5.5000(4) Å. The structure was refined in the anharmonic approximation of thermal atomic vibrations to R w = 0.0047. A total of 78 independent structure amplitudes were measured; 14 parameters were refined; sinθ/λ ≤1.13 Å−1. In the structure under study, the replacement of the divalent Ca2+ cations by the trivalent Gd3+ cations in the position 4a (0, 0, 0) resulted in the statistical distribution of the fluorine atoms over three positions of the sp. gr. Fm3m. Thus, the fluorine atoms occupy the position 8c (1/4, 1/4, 1/4), the main position in the fluorite structure type, and the position 32f (v, v, v) with v = 0.417(1) on threefold symmetry axes. In addition, some fluorine atoms are shifted from the main 8c position along the threefold symmetry axis to the position 32f (w, w, w) with w = 0.313(2).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1312907
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