A new anion, [Hg 2(SCN) 7] 3−: First synthesis, spectroscopic characterization and X-ray structure determination of [Co(NH 3) 6][Hg 2(SCN) 7

Abstract

The reaction of [Co(NH 3) 6]Cl 3 with a mixture of HgCl 2 and NH 4SCN in 1:2:8 molar ratio in hot aqueous medium leads to formation of a new complex salt, [Co(NH 3) 6][Hg 2(SCN) 7] ( 1) in 70% yield. This hexaamminecobalt(III) complex salt has been characterized by elemental analyses, solubility measurement and spectroscopic techniques (e.g. UV/Visible, IR and 13C NMR). Single crystal X-ray structure determination of 1 revealed the presence of discrete [Co(NH 3) 6] 3+ cation and a new anion, [Hg 2(SCN) 7] 3−. This is the first report of a complex salt containing the new anion. The crystal lattice of the complex salt is stabilized by electrostatic forces of attraction and N–H…N (thiocyanate) hydrogen bonding interactions.