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Compositionally induced phase transitions and symmetry relations between space groups in the layered system FeIn 1− x Y x Ge 2 O 7
Author(s) -
Moreno-Tovar Rosario,
Bucio Lauro,
Rosales Ivonne,
Orozco Eligio
Publication year - 2018
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520618009654
Subject(s) - crystallography , valence (chemistry) , crystal structure , space group , rietveld refinement , symmetry (geometry) , chemistry , atom (system on chip) , group (periodic table) , yttrium , x ray crystallography , physics , diffraction , mathematics , geometry , quantum mechanics , oxide , organic chemistry , computer science , embedded system
Symmetry reduction in the basic structure of thortveitite‐type compound FeInGe 2 O 7 – mC 22 ( C 12/ m 1, No. 12) promoted by the incorporation of yttrium in the formula FeIn 1− x Y x Ge 2 O 7 gives rise to a derivative structure called thortveitite‐like AA ′Ge 2 O 7 – mP 44, with symmetry described by the space group P 12 1 / m 1 (No. 11) for x = 0.50, 0.75 and 0.90. The structure remains unchanged within the structural type of thortveitite when x = 0.25. In order to establish structural models for performing a Rietveld refinement to the derivative structure, symmetry relations between space groups connecting the basic and derivative structures were used. The higher contrast to X‐rays of Fe 3+ , In 3+ and Y 3+ as well as by the behaviour during the refinements of the isotropic thermal displacements, the values of interatomic distances and calculated bond‐valence sums for each atom in the asymmetric unit, were helpful for elucidating the relocation of cations in the different available crystallographic sites generated by the symmetry reduction.