Crystal chemistry of Co-doped Zn{sub 7}Sb{sub 2}O{sub 12}

Journal Article · Fri Feb 15 04:00:00 EST 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.11.025· OSTI ID:21043896

Harrington, Richard ^[1]; Miles, Gabrielle C; West, Anthony R ^[1]

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1. Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

Zn{sub 7}Sb{sub 2}O{sub 12} forms a full range of Co-containing {alpha} solid solutions, Zn{sub 7-x}Co{sub x}Sb{sub 2}O{sub 12}, with an inverse-spinel structure at high temperature. At low temperatures for x<2, the solid solutions transform into the low temperature {beta}-polymorph. For x=0, the {beta}{yields}{alpha} transition occurs at 1225{+-}25 deg. C; the transition temperature decreases with increasing x. At high x and low temperatures, {alpha} solid solutions are formed but are non-stoichiometric; the (Zn+Co):Sb ratio is >7:2 and the compensation for the deficiency in Sb is attributed to the partial oxidation of Co{sup 2+} to Co{sup 3+}. From Rietveld refinements using ND data, Co occupies both octahedral and tetrahedral sites at intermediate values of x, but an octahedral preference attributed to crystal field stabilisation, causes the lattice parameter plot to deviate negatively from the Vegard's law. Sub-solidus compatibility relations in the ternary system ZnO-Sb{sub 2}O{sub 5}-CoO have been determined at 1100 deg. C for the compositions containing {<=}50% Sb{sub 2}O{sub 5}. - Graphical abstract: Zn{sub 7}Sb{sub 2}O{sub 12} forms a full range of Co-containing {alpha} solid solutions, Zn{sub 7-x}Co{sub x}Sb{sub 2}O{sub 12}, with an inverse-spinel structure at high temperature. From the Rietveld refinement using ND data, Co occupies both octahedral and tetrahedral sites at intermediate values of x, but an octahedral preference attributed to crystal field stabilisation, causes the lattice parameter plot to deviate negatively from the Vegard's law.

• OSTI ID: 21043896
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 181; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANTIMONY OXIDES
COBALT IONS
COBALT OXIDES
CRYSTAL FIELD
DOPED MATERIALS
LATTICE PARAMETERS
PHASE DIAGRAMS
SEMICONDUCTOR RESISTORS
SOLID SOLUTIONS
SPINELS
TEMPERATURE RANGE 1000-4000 K
TRANSITION TEMPERATURE
VEGARD LAW
ZINC OXIDES