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The Order–Disorder (OD) Polytypism of [Cu 2 ZnTeO 4 ] 2+ [SO 4 ·H 2 O] 2−
Author(s) -
Stöger Berthold,
Weil Matthias,
Missen Owen P.,
Mills Stuart J.
Publication year - 2020
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201900182
Subject(s) - order (exchange) , crystallography , reflection (computer programming) , crystal structure , crystal (programming language) , materials science , physics , chemistry , finance , computer science , economics , programming language
[Cu 2 ZnTeO 4 ] 2+ [SO 4 ·H 2 O] 2− crystallizes as a category IV order‒disorder (OD) structure with two kinds of nonpolar layers with the formal composition [Cu 2 ZnTeO 4 ] 2+ and [SO 4 ·H 2 O] 2− , respectively. Reflection symmetry that is only valid for the [Cu 2 ZnTeO 4 ] 2+ layers leads to two ways of placing the [SO 4 ·H 2 O] 2− layers. Two of the polytypes are of a maximum degree of order (MDO 1 : P 2 1 / m and MDO 2 : Pnma ). The crystal under investigation is mostly of the MDO 2 polytype. Remaining positive electron density peaks in the difference Fourier maps indicate fragments of the MDO 1 polytype.