5892-22-8Relevant academic research and scientific papers
Ca(SCN)2 and Ca(SCN)2·2 H2O: Crystal structure, thermal behavior and vibrational spectroscopy
Wickleder, Claudia,Larsen, Patrick
, p. 1419 - 1426 (2007/10/03)
The dehydration of Ca(SCN)2·4H2O yields single crystals of Ca(SCN)2·2 H2O as well as of Ca(SCN)2. Ca(SCN)2·2 H2O crystallizes with a hitherto unknown structure (orthorhombic, Pnma, Z = 4, a = 1280.1(2), b = 790.3(1), c = 726.9(1) pm, Rall = 0.0430). The Ca2+ ions are surrounded by four SCN- ions and four water molecules. The polyhedra are connected to chains along [010] via common oxygen atoms. The SCN- ions connect these chains to a three-dimensional network so that each thiocyanate group is linked to two Ca2+ ions. Hydrogen bonding with sulfur atoms as acceptors is observed. The crystal structure of Ca(SCN)2 (monoclinic, C2/c, Z = 4, a = 961.7(2), b = 642.4(2), c = 787.2(2) pm, Rall = 0.0673) consists of alternating layers of Ca2+ and SCN- ions. The cations are surrounded by four sulfur and four nitrogen atoms in form of a square antiprism. According to ∞3[Ca(SCN)8/4] each SCN- ion connects four Ca2+ ions with each other. Thermal investigations show a phase transition of Ca(SCN)2·4 H2O followed by dehydration to Ca(SCN)2 which finally decomposes yielding CaS. IR and Raman measurements have been performed and the resulting frequencies assigned and discussed.
