Investigation of the structure and properties of (K x (NH4)1 − x )3H(SO4)2 single crystals

Abstract

The influence of isomorphous replacement in the cation sublattice on the kinetics of the phase transition in single crystals of the solid solutions (Kx(NH4)1 − x)mHn(SO4)(m + n)/2 · yH2O belonging to the K3H(SO4)2-(NH4)3H(SO4)2-H2O salt system was studied. Superproton phase transitions for the end compositions of this system have been found earlier. The optical and thermal properties of crystals with the composition (K,NH4)3H(SO4)2 in the temperature range from 295 to 500 K were investigated, and the crystal structure was determined at 295 K. The results of the study and the comparison with the literature data show that the replacement of potassium atoms with ammonia leads to a fundamental change in the kinetics of the phase transition, the phase-transition temperature remaining virtually unchanged.