New mixed-valence chromium structure type: NH{sub 4}Cr(CrO{sub 4}){sub 2}

Journal Article · Sun Jan 15 04:00:00 EST 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.10.021· OSTI ID:20784861

Casari, Barbara M ^[1]; Wingstrand, Erica ^[2]; Langer, Vratislav ^[3]

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1. Department of Chemistry, Inorganic Chemistry, Goeteborg University, SE-421 96 Goeteborg (Sweden)
2. Department of Chemistry, Organic Chemistry, Royal Institute of Technology, SE 100 44 Stockholm (Sweden)
3. Department of Chemical and Biological Engineering, Division of Material and Surface Chemistry, Subdivision of Inorganic Environmental Chemistry, Chalmers University of Technology, SE-421 96 Goeteborg (Sweden)

Synthesis and crystal structure of a new structure type of mixed Cr(III)/Cr(VI) chromates is reported. NH{sub 4}Cr(CrO{sub 4}){sub 2} was prepared from CrO{sub 3} in the presence of (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6}. Since this is the first preparation of mixed valence ternary chromium oxides from aqueous solution, a reaction pathway for this synthesis is suggested. The crystal structure of NH{sub 4}Cr(CrO{sub 4}){sub 2} has been determined from three-dimensional X-ray data collected at low temperature, 173K. The structure belongs to the orthorhombic space group Pnma, with a=14.5206(10), b=5.4826(4), c=8.7041(7)A and Z=4. The title compound consists of corner-sharing chromium(III) octahedra and chromium(VI) tetrahedra forming a three-dimensional network with the composition [Cr(CrO{sub 4}){sub 2}]{sub n}{sup n-}, containing channels in which zigzag rows of ammonium ions balance the net charge.

• OSTI ID: 20784861
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 179; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AMMONIUM COMPOUNDS
AQUEOUS SOLUTIONS
CHROMATES
CHROMIUM OXIDES
NITRATES
ORTHORHOMBIC LATTICES
REDOX REACTIONS
SPACE GROUPS
SYNTHESIS
VALENCE
X-RAY DIFFRACTION