THE PHASE-DIAGRAM OF CD4-KR

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