We report on a Raman scattering study of the LiCoO2, gamma-Na0.7CoO2 and Li0.42Na0.36CoO2 phases. The Raman spectrum of the ordered cobaltite Li0.42Na0.36CoO2 consists of a set of seven distinct peaks with the wave numbers around 190, 445, 467, 513, 572, 609 and 674 cm (1). It exhibits features of the spectra for LiCoO2 and gamma-Na0.7CoO2 and therefore can be considered as a superposition of these two spectra. It may be supposed that in the structure of the double cobaltite the bonding between sodium-and lithium-containing blocks is rather weak. (C) 2010 Elsevier B. V. All rights reserved.