Аннотация:The phosphates of the CsMPO4 (M – Mg, Mn, Co) compositions were synthesized by crystallization from solutions
containing the elements that form the target products. The crystalline compounds were characterized by the X-ray diffraction,
electron microscopy and microprobe analysis. The compounds crystallized in the β-tridymite type structure. The ceramics
showed volume thermal expansion coefficients of (3–7)·10-5 K-1. The heat capacity of the compounds was measured in the
temperature range from 5 to 650 K, the entropies of formation at 298.15 K were determined. The thermal diffusivity and
the thermal conductivity of the ceramic samples were studied in the range from 298 to 473 K. The level of thermophysical
characteristics of the studied phosphate ceramics exceed those of well-known thermo-insulating materials, such as commercial
stabilized ZrO2. The cesium leaching from the phosphate CsMgPO4 was studied. The evaluated leaching resistance of CsMgPO4
was comparable with that of a borosilicate glass.