The absorption spectrum at room temperature and liquid helium temperature and the magnetic circular dichroism (MCD) spectrum at liquid helium temperature are reported for ∼15 per cent Mn2+in CdF2. The results indicate that even at these concentrations the Mn2+ions occupy undistorted cubal symmetry sites. The intensity is entirely vibronic with at least onet1uvibration of 155 cm-1active. Crystal-field calculations have been used to assign the gross features of the spectrum and the use of MCD has allowed an almost complete elucidation of the fine structure observed. In the two4T2gstates this structure is assigned to the various spin orbit components. The MCD results indicate that vibronic mixing to theground state, rather than to excited states, produces the observed spectrum and that both4T1uand4T2ustates probably mix.