[en] Single crystals of rare earth (RE) bromide chlorides RE Br_xCl_3-x (RE = Ce, Pr, Nd, Sm, Gd) have been prepared by the reaction of rare earth oxides with AlBr₃/AlCl₃ in a given ratio, followed by chemical vapour phase transport with the same agent. The structure and composition of the mixed halides were determined by single crystal X-ray diffraction data. Ce Br_1.08Cl_1.92. PrBr_1.07Cl_1.93, NdBr_1.97Cl_1.03 and respecter SmBr_1.12Cl_1crystallize in the UCl₃-type structure, in the case of GdBr_1.09Cl_1.91 the PuBr₃-type structure is realized. The dependence of the structure type on the Br/Cl ratio is discussed