Abstract Assignments of v as (SMS) and vs (SMS) for the complexes M (SR) 2 (M= Zn, Cd, Hg; R= Et, Bu t) and Hg (SMe) 2 from infrared and Raman spectroscopy are reported. Comparison of frequencies for the complex Hg (SBu t) 2 containing four-coordinate mercury with those of Hg (SR) 2 (R= Me, Et) containing two-coordinate mercury permits assignment of a polymeric structure with linear coordination for the 1: 1 complex of Hg (II) with 2, 3- ...