The Raman and infrared spectra of NiC12.6H20, NiC1,-6Dz0, CoCl,.6H,O, CoC1,-6Dz0 and CoBr,-6H,O single crystals have been measured in the range 3600-30 cm-' (Raman) and 3800-400 cm-' (IR). The water internal modes have been best assigned for NiC12.6H,0, including Fermi resonance effects. The corresponding Raman intensities have been interpreted in terms of the free molecule Raman tensors. Among the lattice vibrations, the metal halide and metal-water stretchings, and also the librations of the MX2.4H20 octahedra, have been identified and assigned.