Syntheses, crystallographic characterization, and structural relations of Rb[SCN]

Abstract

Abstract Colorless rubidium thiocyanate was synthesized by three different approaches. DCS-TGA measurements allowed for extraction of phase transition, melting, and decomposition temperatures. Single-crystal X-ray diffraction showed Rb[SCN] to crystallize in the low-temperature LT-K[SCN] crystal structure type (Pbcm, oP16). Above its phase-transition temperature (432.1 K) the title compound crystallizes with the high-temperature HT-K[SCN] crystal structure type (I4/mcm, tI28) with head-to-tail disordered thiocyanate anions. Both modifications are related to one another and to the LT/HT-Cs[SCN] structure types, and the relation has been studied in detail employing the Bärnighausen formalism. Phase purity and bulk phase transition were confirmed by temperature-dependent PXRD.