  We present low temperature Raman measurements on Ca3Co2O6. Shell model
lattice dynamics calculations were done to determine the vibrational pattern of
the expected Raman modes. In the temperature window 300K to 52K the mode
frequencies and the full width at half maxima (FWHM) of the modes vary in an
expected fashion, i.e., the mode frequencies shift to higher values and the
FWHM decreases with lowering of temperature. At about 52K (T *) there happens
an abrupt change in both the peak position and FWHM. The peak positions show a
sudden softening while FWHM increases abruptly. To explain these spectral
features we postulate that below T * the degeneracy of the high symmetry Eg is
lifted due to the possible distortion of the CoOO6 octahedra.
