Über Cyanatomercurate M2Hg3(NCO)8 (M = K, Rb, Cs) - Synthesen, Kristallstrukturen und Schwingungsspektren / On Cyanatomercurates M2Hg3(NCO)8 (M = K, Rb, Cs) - Syntheses, Crystal Structures and Vibrational Spectra

Abstract

Abstract By mixing aqueous solutions of Hg(CH3COO)2 and MOCN (M = K, Rb, Cs) the tri-clinic compounds M2Hg3(NCO)8 are formed. In a first approximation the crystal structure analysis indicates isolated Hg(NCO)2 molecules besides K+ and NCO- ions. As in the range of van der Waals radii additional NCO-neighbours are noticed the mercury atoms are surrounded by distorted octahedra. The octahedra around 2/3 of the Hg form infinite chains as in KHg(NCO)3 which are linked together by additional Hg(NCO)2 molecules. Therefore the compound can be formulated as a double salt 2 KHg(NCO)3 • Hg(NCO)2. The vibrational spectrum is discussed. Rb2Hg3(NCO)8 is isotypous while the caesium salt has a double cell volume.