Structural phase transitions in elpasolites Rb2NaDyF6and Rb2KDyF6

Abstract
The crystals of Rb2NaDyF6 and Rb2KDyF6 were grown and the optic, thermal and X-ray investigations were made in temperature range 80–450 K. The structural phase transitions were observed in both crystals. But the character of these trams-formations and the distortion type are different.