Cationic distribution in two new trivalent transition metal diphosphates Cd{sub 5}M{sub 2}{sup III} (P{sub 2}O{sub 7}) (M = V, Fe)
- Universite de Caen (France); and others
The two diphosphates, Cd{sub 5}M{sub 2}{sup III}(P{sub 2}O{sub 7}){sub 4} with M - V, Fe, isotypic with Fe{sub 5}{sup II}Fe{sub 2}{sup III}(P{sub 2}O{sub 7}){sub 4}, have been synthesized. They crystallize in the space group C222 with a {approximately}8.8 {angstrom}, b {approximately}9.9 {angstrom}, and c {approximately}24.1 {angstrom}. The single crystal structure determination of the V phase and the Moessbauer spectroscopy study of the Fe phase, show that the cationic distribution is different from that observed in Fe{sub 5}{sup II}Fe{sub 2}{sup III}(P{sub 2}O{sub 7}){sub 4}, i.e., V(III) or Fe(III) is located in two kinds of sites instead of one kind of site. A detailed analysis of this structure shows that its octahedral layers consist of rock salt type ribbons, themselves built up from infinite chains of edge-sharing octahedra, interconnected through trioctahedral units of edge-sharing octahedra. On the basis of this description, the different cationic distribution compared to the pure Fe phase is then explained by the mismatch between infinite octahedral chains and trioctahedral units, due to the larger size of Cd(II) compared to Fe(II).
- OSTI ID:
- 223726
- Journal Information:
- Journal of Solid State Chemistry, Vol. 121, Issue 2; Other Information: PBD: 1 Feb 1996
- Country of Publication:
- United States
- Language:
- English
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