Layered structures of hydrated vanadium oxides. Part 1.—Alkali-metal intercalates A0.3V2O5·nH2O (A = Na, K, Rb, Cs and NH4)

Abstract

Layered structures of the alkali-metal intercalates of hydrated vanadium oxides A_0.3V₂O₅·nH₂O (A = Na, K, Rb, Cs and NH₄) have been studied by the X-ray Rietveld method and electron diffraction. Structural analysis was performed for both hydrated and dehydrated phases, in which the (00l) reflections were used in the Rietveld method because of the preferred orientation of samples. The structures are approximated by atomic sheets: two V₂O₅ sheets and one interlayer sheet of alkali-metal ions and water molecules. The pair of V₂O₅ sheets are 2.7 Å apart and form a double-sheet V₂O₅ layer, which is proposed to be closely related to the V₂O₅ layer of δ-Ag_xV₂O₅.