Аннотация:The thermal conductivity k of a series of single crystals of Na0.4(Y1 – xNdx)0.6F2.2 (x = 0–0.5) solid solutions has been measured in the range 50–300 K by an absolute steady-state axial heat flow technique. The temperature behavior of thermal conductivity for all of the crystals is characteristic of disordered materials. The room-temperature thermal conductivity of the solid solutions is low: k = 1.1–1.4 W/(m K).