Probing the structures and thermodynamic characteristics of the environment polluting mercuric halides, cyanides and thiocyanates

► CCSD calculations on the compounds HgX+, HgX2, HgX3-, and HgX42- (X = Cl, Br, I, CN, and SCN) to determine their structures in the gas phase. ► Solvation calculations using CPCM model at the CCSD level on the optimized structures of these molecules to determine their stepwise standard Gibbs free energy of formation in aqueous medium (ΔGaq∘) starting from simple Hg2+ and X− ions. ► The computed ΔGaq∘ values correlate linearly with experimental data.