6Li-7Li isotopic shifts in the infrared spectrum of inorganic lithium compounds-II. Rhombohedral LiXO2 compounds

The infrared spectrum of some LiXIIIO2 compounds (XIII = Al, Ga, Co, Cr, Rh, Sc) with an ordered distribution of Li and XIII cations on octahedral sites has been investigated with the help of 6Li-7Li isotopic replacement. The spectrum is essentially characterized by the occurrence of distinct, well individualized, XIIIO6 (in the 650-400 cm-1 region) and LiO6 (in the 300-200 cm-1 region) frequencies. However, this vibrational behaviour seems to be restricted to the compounds with the rhombohedral R3̄m structure and cannot be generalized to all LiXO2 compounds. Some specific features of the individual spectra have also been discussed. © 1970.