INTERLAYER WATER-MOLECULES OF VANADIUM PENTOXIDE HYDRATE .4. CALORIMETRY OF WATER IN THE SAMPLES INTRINSIC AND INTERCALATED WITH LI, K, MG, AND AL IONS BELOW 0-DEGREES-C

The melting processes of frozen H2O in the vanadium pentoxide hydrates, which were intrinsic and intercalated with Li+, K+, Mg2+, and Al3+, were studied at -100 to +25-degrees-C. The specific amount of H2O molecules in the samples, which depends upon the ionic intercalant, is not frozen at low temperatures (even down to -150-degrees-C). It corresponds to the adsorption limit below the saturated H2O vapor pressure. In the intrinsic and intercalated samples with Li+, additional H2O molecules over the nonfreezing H2O can be molten in a mode different from pure ice; i.e., frozen H2O is molten at temperatures much below 0-degrees-C. The melting process was explained by the adsorption of H2O into the solid from the vapor phase and the sublimation of ice outside of the solid. Of the samples intercalated with ions other than Li+, additional H2O over nonfreezing H2O is not intercalated under moderately wet conditions between the layers and behaves similarly to pure H2O.