Raman spectroscopic study of LiVO3 and LiVO3·2H2O

Abstract The Raman spectra of lithium metavanadate, LiVO 3 , have been recorded in the temperature range 300-10 K. A phase transition was observed at about 70 K. A soft mode was found for the room temperature phase at 55 cm −1 , while at least two soft modes were observed for the low temperature phase at 213 and 289 cm −1 respectively. The hydrated samples LiVO 3 ·2H 2 O were also studied. It was found that the samples grown from supersaturated aqueous solutions contained only water molecules adsorbed on the crystal surface and these can be eliminated by heating to 70°C, while the samples grown from unsaturated solution have water molecules inside the sample as well as on the surface, and a higher temperature of 130°C is needed to release the internal water. The hydrated samples may transform to LiVO 3 through an intermediate phase.