The optical properties of BaBrI crystals doped with cerium ions were studied. The possible types of cerium-containing luminescence centers are established. Based on the experimental data obtained for trivalent lanthanides, a Dorenbos diagram was constructed. According to the results of the study of the luminescence spectra measured under X-ray excitation, possible energy transfer mechanisms are assumed. This work was supported by the Russian Science Foundation, a grant of the Russian Science Foundation 17-72-10084: spectroscopy of cerium and cerium-oxygen centers, determination of cerium concentration in crystals, analysis of the results obtained. Some of the crystals investigated in the article were grown as part of the government assignment 0350-2016-0024. The data in the work were obtained using the scientific equipment of the Collective Scientific Center "Isotope-geochemical studies" of the IHP SB RAS.