Properties of the cubic cyanospinels (RbxK1−x)2Hg(CN)4

Abstract

Abstract Homogeneous single crystals of the cubic phase of the solid solution series (Rb x K1−x )2Hg(CN)4 have been grown from aqueous solutions in the composition range 0 < x < 0.77. A nearly constant partition coefficient of ca. 1 for the rubidium content in the solid phase and in the solution was observed over the whole range of composition. Lattice constants, densities, and the pressure derivatives of the transition temperatures vary quasilinearly with composition in accordance with Vegard's rule. Transition temperatures and transition enthalpies exhibit a distinct deviation from a linear dependence at low rubidium contents. Elastic and thermoelastic constants determined on a crystal with x = 0.68 show the same type of anomalies as K2Hg(CN)4. Owing to the strong dependence of transition temperature on composition, any crystal possessing a certain transition temperature within the range between 110 and 398 K can be easily realized.