[en] Radioluminescence of cadmium sulfide single crystals doped with tellurium and mercury and of zinc sulfide and selenide single crystals doped with tellurium is examined. Single crystals have been grown from a melt under pressure. Radioluminescence is excited by X-ray at 8-10 keV up to 1 MeV. The radioluminescence spectra are studied in the range of 90-300 K. The effect of the impurity concentration on the radiation intensity is analyzed. The data obtained allow one to make a supposition on a mechanism of radioluminescence. Most probable mechanism is radiative recombination on the centres which are inherent defects of the lattice. An isovalence impurity is not so important in this case. It helps the formation of inherent defects of the lattice and results in their freezing with increasing temperature. A conclusion is made that efficiency of radioluminescence of A²B⁶ compounds with an isovalence impurity is not second to that of already well-known scintillators