LAYERED STRUCTURES OF HYDRATED VANADIUM-OXIDES .1. ALKALI-METAL INTERCALATES A0.3V2O5.NH2O (A = NA, K, RB, CS AND NH4)

Layered structures of the alkali-metal intercalates of hydrated vanadium oxides A0.3V2O5.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 (001) 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 angstrom apart and form a double-sheet V2O5 layer, which is proposed to be closely related to the V2O5 layer of delta-AgxV2O5.