THE PHASE-DIAGRAM OF CD4-KR

X-ray powder diffraction studies are performed on solid CD4-Kr solutions from helium to their melting points at Kr concentration 20-35%. The phase boundaries are specified in the phase equilibrium diagram. A region of two coexists phases is revealed at T > 24 K. The phases have the similar fcc-symmetries but differ in molar volumes and apparently in the degree of the rotational motion retardation of CD4 molecules in them. This region corresponds to the krypton concentrations in deuteromethane 28-32% at 24 K, the critical concentration being x(c) congruent-to 29% Kr. Unlike other binary cryosolutions, this system is noted for the narrowest region of stratification into two isomorphic phases (approximately (5 +/- 2)%) and the lowest critical temperature (approximately 52 K).