Metal Vacancy Ordering in an Antiperovskite Resulting in Two Modifications of Fe2SeO

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• 作者：Dr. Martin Valldor ; Taylor Wright ; Prof. Dr. Andrew Fitch and Dr. Yurii Prots
• 刊名：Angewandte Chemie International Edition
• 出版年：2016
• 出版时间：August 1, 2016
• 年：2016
• 卷：55
• 期：32
• 页码：9380-9383
• 全文大小：2564K
• ISSN：1521-3773

文摘

Small, red Fe<sub>2sub>SeO single crystals in two modifications were obtained from a CsCl flux. The metastable α-phase is pseudo-tetragonal (Cmce, a=16.4492(8) Å, b=11.1392(4) Å, c=11.1392(4) Å), whereas the β-phase is trigonal (P3<sub>1sub>, a=9.8349(4) Å, c=6.9591(4) Å)) and thermodynamically stable within a narrow temperature range. Both crystal structures were solved from twinned specimens. The enantiomers of the β-phase appear as racemic mixtures. Selenium and oxygen form two individual interpenetrating primitive cubic lattices, giving a bcc packing. A quasi-octahedrally coordinated iron atom is found close to the center of each surface of the selenium sublattice. The difference between the α- and β-phases is the distribution of iron at 2/3 of the surfaces. α- and β-Fe<sub>2sub>SeO are comparable with metal-vacancy-ordered antiperovskites. Each Fe/O lattice can also be described in terms of vertex-sharing OFe<sub>4sub> tetrahedra, with a crystal structure similar to that of an antisilicate. Iron is divalent and has a high-spin d<sup>6sup> (S=2) configuration. The β-phase exhibits magnetoelectric coupling.