Ionisation (2 + -to-3 + or 1 +) and intra-shell transitions of iron in bulk crystals of ZnS, ZnSe, CdSe and in their alloys are studied. The results of these studies allow us to verify the recent theoretical predictions on universal reference levels due to transition metal ions and to explain the nature of Fe-related nonradiative transitions ill ZnSe. We also demonstrate limitations of the Ludwig-Woodbury model for the description of intra-shell transitions of Fe2+.