Partial charge ordering in the mixed-valent compound (Bi{sub 6}O{sub 5})Rh{sub 8}{sup 3+}Rh{sub 4}{sup 4+}O{sub 24}

Journal Article · Sat Dec 15 04:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.09.031· OSTI ID:21043775

Mizoguchi, H ^[1]; Marshall, W J ^[2]; Ramirez, A P ^[3]; Sleight, A W ^[1]

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1. Department of Chemistry and OSUMI, Oregon State University, Corvallis, OR 97331-4003 (United States)
2. Central Research and Development, Dupont Company, Experimental Station, Wilmington, DE 19880-0228 (United States)
3. Bell Laboratories, Alcatel-Lucent, 600 Mountain Avenue, Murray Hill, NJ 07974 (United States)

Crystals of the mixed-valent compound (Bi{sub 6}O{sub 5})Rh{sub 8}{sup 3+}Rh{sub 4}{sup 4+}O{sub 24} were grown from a flux. The room temperature conductivity of a crystal was 3 S/cm but decreased smoothly with decreasing temperature to 10{sup -5} S/cm at 25 K. Magnetic susceptibility data indicate a localized moment for Rh{sup 4+}. A Seebeck coefficient at 200 K of +280 {mu}V/K further confirms that this compound is a semiconductor rather than a metal with a partially filled 4d t{sub 2g} band. A structure refinement based on single crystal X-ray diffraction data obtained at 173 and 296 K provided Rh-O distances sufficiently accurate to indicate the nature of the charge ordering between Rh{sup 3+} and Rh{sup 4+}. The large Seebeck coefficient coupled with the high electrical conductivity indicates that this may be a promising low-temperature thermoelectric material. - Graphical abstract: Crystals of the mixed-valent compound (Bi{sub 6}O{sub 5})Rh{sub 8}{sup 3+}Rh{sub 4}{sup 4+}O{sub 24} show semiconducting properties, and magnetic susceptibility data indicate a localized moment for Rh{sup 4+}. Structure refinements at 173 and 296 K show partial charge ordering between Rh{sup 3+} and Rh{sup 4+}.

• OSTI ID: 21043775
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BISMUTH OXIDES
ELECTRIC CONDUCTIVITY
MAGNETIC SUSCEPTIBILITY
MONOCRYSTALS
RHODIUM IONS
RHODIUM OXIDES
SEMICONDUCTOR MATERIALS
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THERMOELECTRIC MATERIALS
X-RAY DIFFRACTION