Crystal and molecular structure of a lattice adduct, HgPh2·2[Hg(SCN)2(PPh3)2]: an unusual case of two-and four-co-ordinate mercury in the same unit cell

Abstract

Reaction of phenylmercury(II) thiocyanate with triphenylphosphine in ethanol formed a product of unusual stoicheiometry, HgPh₂·2[Hg(SCN)₂(PPh₃)₂] which has been characterised by X-ray crystallography. The complex crystallises in the triclinic space group P with unit-cell parameters a= 10.426(1), b= 19.576(3), c= 9.821(2)Å, α= 94.26(3), β= 97.00(4), and γ= 87.08(2)°. Four-co-ordinate Hg(SCN)₂(PPh₃)₂ molecules represent a new crystalline modification of the previously reported monoclinic form. The adduct HgPh₂·2[Hg(SCN)₂(PPh₃)₂] represents an unusual case of the existence of two-co-ordinate linear Hg^II and distorted tetrahedral Hg^II in the same unit cell.