The red chem iluminescence (CL) of coordinatively unsaturated surface chromium(II) compounds in their reaction with O2 has been studied at various reactivities of the products and various reaction temperatures. With compounds of high reactivity, two CL’s were observed: the first - spectrally unstructured - appears at T ≧ -130 °C, the second - being more intense and spectrally well structure - at T ≧ -90 °C. In course of both these CL’s O2 is released. - Below -130 °C, oxidation takes place without any luminescence. On heating of the reaction product in vacuo, the luminescence phenomena are observed as a two-stage thermoluminescence (TL). With the final oxidation product, a photoluminescence (PL) can be stimulated by UV irradiation which is identical with the second CL and shows a well resolved vibrational fine structure at -196 °C. Probably this PL as well as the second CL is produced essentially by an undisturbed monochromate surface species. The first CL and a small part o f the PL is attributed to a topologically broad population of a “disturbed” chromate surface species. Surface chromium(II) compounds of low reactivity show a one-component CL, TL and PL, almost identical with the first CL mentioned above; they obviously contain the ‘"disturbed” species only. The mentioned species, defined by their luminescence behaviour, are postulated to be members of the known families of surface chromium occurring in Phillips catalysts, CrA II and CrB II, respectively.