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Ba 4 Cr 2 US 9 : The First Chalcogenide Analogue of the Perovskite-related (A 3 A′BO 6 ) m (A 3 B 3 O 9 ) n Family
| Content Provider | Semantic Scholar |
|---|---|
| Author | Yao, Jiyong Ibers, James A. |
| Copyright Year | 2008 |
| Abstract | The compound Ba4Cr2US9, which crystallizes in space group P321, consists of one-dimensional 1 [Cr2US9 ] chains separated by Ba2 cations. Each one-dimensional chain comprises facesharing CrS6 octahedra and US6 trigonal prisms in the sequence Low-dimensional inorganic structures are of great interest in solidstate chemistry and material sciences because of their physical properties. One of the structure types heavily studied in recent years is the (A3A BO6)m(A3B3O9)n homologous series whose structures are related to the 2H-hexagonal perovskites. Here A is usually an alkaline-earth cation, A (which can be the same element as A or B) is a cation in a trigonal prismatic environment, and B is a cation in an octahedral environment. A 2H-hexagonal perovskite is often thought of as a pseudo-hexagonal closest-packed stack of AO3 layers with the transition metal B occupying the octahedral holes between the layers to give the stoichiometry ABO3 (sometimes more conveniently written as A3B3O9). An A3O6 layer can be formed by the ordered removal of three O2 anions from an A3O9 layer to create holes inside trigonal prisms of O2 anions. When these holes are occupied by A cations, the stoichiometry of the layers becomes A3A O6. If the stacking sequence of the A3A O6 and the A3O9 layers is allowed to vary, a series of compounds can be formed with the general formula (A3A BO6)m(A3B3O9)n (m 1, n 0). The structure features one-dimensional chains of ordered arrays of A O6 trigonal prisms and BO6 octahedra, separated by A2 cations. Many compounds have been synthesized in this homologous series, including Sr4PtO6 (A A , m ) [1], Ba6Ni5O15 (A B, m 1. n 1) [2], Sr9Ni6.64O21 (A B, m 2. n 1) [3], Ca3Co2O6 (A B, m ) [4], and Sr4Mn2MO9 (M Zn, Cu) (A B, m 3. n 1) [5]. Some of these compounds exhibit interesting magnetic properties. For example, Ca3Co2O6 [4] exhibits intrachain and interchain magnetic ordering at 24 K and 12 K, respectively; Sr4Ir2MO9 (M Zn, Cu) (m 1, n 1) [6] and Ba6Mn4MO15 (M Zn, Cu) [7] show three-dimensional antiferromagnetic ordering at 1.6 K and 6 K, respectively. All the compounds reported in this homologous series are oxides. No related chalcogenides are known. Yet these would be interesting because the increased covalency of the metal-chalcogen bond compared to the metal-oxygen bond will likely lead to compounds with electronic structures and physical properties different from the oxides. * Prof. Dr. James A. Ibers Department Chemistry, Northwestern University Evanston, IL / USA E-mail: ibers@chem.northwestern.edu Z. Anorg. Allg. Chem. 2008, 634, 1645 1647 © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1645 oct oct tp oct oct tp with the U and Cr centers in a linear chain parallel to [001]. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://chemgroups.northwestern.edu/ibers/Publications/Ba4Cr2US9.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
