Crystal structure and magnetic properties of two new cobalt selenite halides: Co{sub 5}(SeO{sub 3}){sub 4} X {sub 2} (X=Cl, Br)
- Department of Inorganic Chemistry, Stockholm University, S-106 91 Stockholm (Sweden)
- Institute of Physics, P.O. Box 304, HR-10000 Zagreb (Croatia)
- Institut de Physique de la Matiere Complexe, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)
Two new isostructural cobalt selenite halides Co{sub 5}(SeO{sub 3}){sub 4}Cl{sub 2} and Co{sub 5}(SeO{sub 3}){sub 4}Br{sub 2} have been synthesized. They crystallize in the triclinic system space group P-1 with the following lattice parameters for Co{sub 5}(SeO{sub 3}){sub 4}Cl{sub 2}: a=6.4935(8) A, b=7.7288(8) A, c=7.7443(10) A, {alpha}=66.051(11){sup o}, {beta}=73.610(11){sup o}, {gamma}=81.268(9){sup o}, and Z=1. The crystal structures were solved from single-crystal X-ray data, R1=3.73 and 4.03 for Co{sub 5}(SeO{sub 3}){sub 4}Cl{sub 2} and Co{sub 5}(SeO{sub 3}){sub 4}Br{sub 2}, respectively. The new compounds are isostructural to Ni{sub 5}(SeO{sub 3}){sub 4}Br{sub 2}. Magnetic susceptibility measurements on oriented single-crystalline samples show anisotropic response in a broad temperature range. The anisotropic susceptibility is quantitatively interpreted within the zero-field splitting schemes for Co{sup 2+} and Ni{sup 2+} ions. Sharp low-temperature susceptibility features, at T {sub N}=18 and 20 K for Co{sub 5}(SeO{sub 3}){sub 4}Cl{sub 2} and Co{sub 5}(SeO{sub 3}){sub 4}Br{sub 2}, respectively, are ascribed to antiferromagnetic ordering in a minority magnetic subsystem. In isostructural Ni{sub 5}(SeO{sub 3}){sub 4}Br{sub 2} magnetically ordered subsystem represents a majority fraction (T {sub N}=46 K). Nevertheless, anisotropic susceptibility of Ni{sub 5}(SeO{sub 3}){sub 4}Br{sub 2} is dominated at low temperatures by a minority fraction, subject to single-ion anisotropy effects and increasing population of S{sub z} =0 (singlet) ground state of octahedrally coordinated Ni{sup 2+}. - Graphical abstract: Two new iso-structural cobalt selenite halides Co{sub 5}(SeO{sub 3}){sub 4}Cl{sub 2} and Co{sub 5}(SeO{sub 3}){sub 4}Br{sub 2} have been synthesized which are iso-structural to Ni{sub 5}(SeO{sub 3}){sub 4}Br{sub 2}. Magnetic susceptibility measurements on oriented single-crystalline samples show anisotropic response in a broad temperature range, revealing significant single-ion anisotropy effects.
- OSTI ID:
- 21015746
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 3; Other Information: DOI: 10.1016/j.jssc.2006.12.035; PII: S0022-4596(07)00016-3; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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