A large series of isotypic Mo(V) diphosphates with a tunnel structure: From A(MoO){sub 10}(P{sub 2}O{sub 7}){sub 8} with A=Ba, Sr, Ca, Cd, Pb to A(MoO){sub 5}(P{sub 2}O{sub 7}){sub 4} with A=Ag, Li, Na, K
- Laboratoire CRISMAT-ENSICAEN, UMR CNRS 6508, 6 boulevard du marechal Juin, 14050 CAEN cedex (France)
The single crystal structure of a series of nine isotypic Mo(V) diphosphates was determined from crystals with composition A {sup 2+}(MoO){sub 10}(P{sub 2}O{sub 7}){sub 8} (A=Ba, Sr, Ca, Cd, Pb) and A {sup +}(MoO){sub 5}(P{sub 2}O{sub 7}){sub 4} (A=Ag, Li, Na, K). The structure of those phosphates, built up of corner sharing MoO{sub 6} octahedra, MoO{sub 5} tetragonal pyramids and P{sub 2}O{sub 7} diphosphates groups, forms eight-sided tunnels as described by Lii et al. for A=Ag. New features are evidenced: (1) existence of two orientations, up and down along b for the MoO{sub 5} pyramids; (2) maximum insertion rate of the divalent cations which is twice less than that of the univalent cations; (3) different behavior of the series 'Pb, Sr, Ba, Li, Na, K' which exhibits only one kind of site for the inserted cation, compared to the 'Cd, Ca, Ag' series for which two kinds of sites are observed; (4) off-centering of the A-site cations with respect to the tunnel axis; and (5) unusually high thermal factors along the tunnel axis, but absence of ionic conductivity. - Graphical abstract: The structure of Pb(MoO){sub 10}(P{sub 2}O{sub 7}){sub 8} viewed along b with the Pb ions in the octagonal tunnels.
- OSTI ID:
- 21015871
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 7; Other Information: DOI: 10.1016/j.jssc.2007.05.004; PII: S0022-4596(07)00194-6; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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