This paper describes results of experimental studies on radiation defects in nominally pure single crystals of corundum in two initial states: α-Al 2 O 3 with an unperturbed lattice and α-Al 2 O 3 :C with a high concentration of anion vacancies. Defects were identified from optical absorption spectra, ion-oluminescence, pulsed cathodoluminescence and photoluminescence spectra. It is shown that mostly color centers of the F- and F + -types are formed in the α-Al 2 O 3 lattice under irradiation with 5,7 MeV protons.