New mixed-valence chromium structure type: NH4Cr(CrO4)(2)
2006 (English)In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 179, no 1, 296-301 p.Article in journal (Refereed) Published
Synthesis and crystal structure of a new structure type of mixed Cr(III)/Cr(VI) chromates is reported. NH4Cr(CrO4)(2) was prepared from CrO3 in the presence of (NH4)(2)Ce(NO3)(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 NH4Cr(CrO4)2 has been determined from three-dimensional X-ray data collected at low temperature, 173 K. The structure belongs to the orthorhombic space group Pnma, with a = 14.5206(10), b = 5.4826(4), c = 8.7041(7) angstrom 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(CrO4)(2]n)(n-), containing channels in which zigzag rows of ammonium ions balance the net charge.
Place, publisher, year, edition, pages
2006. Vol. 179, no 1, 296-301 p.
NH4Cr3O8, mixed-valence ternary oxide, mixed-valence chromate, Cr(VI)/Ce(III) redox reaction, X-ray diffraction
IdentifiersURN: urn:nbn:se:kth:diva-37468DOI: 10.1016/j.jssc.2005.10.021ISI: 000234807500039ScopusID: 2-s2.0-30144434770OAI: oai:DiVA.org:kth-37468DiVA: diva2:433960