[en] It is known that the RENi₂ compounds crystallize in the cubic C15-type structure. Measurements of the high temperature resistivity show discontinuities in connection with hysteresis loops at 630K for GdNi₂, 690K for YNi₂ and 950K for SmNi₂. No such anomalies have been found in the other RENi₂ compounds. X-ray diffraction analysis performed above these transition temperatures reveals a more complex pattern then for the low temperature C15-type structure. The reason for the change in structure which is reversible can at least be explained phenomenologically by the fact that the R_RE/R_Ni ratio exceeds a critical value in these three compounds at high temperature