Vibrational Spectrum and Force Constants of Au(CN)4—

Raman and infrared spectra of aqueous and solid KAu(CN)4 have been studied. Ten of the 16 fundamental vibrations of the Au(CN)4— ions have been assigned. The stretching force constants and some of the bending force constants have been calculated. The high CN force constant (17.4 mdyn/Å) and high MC force constant (3.0 mdyn/Å) indicate strong metal—ligand sigma bonding and weak metal—ligand pi bonding, as expected because of the high effective nuclear kernel charge on the gold.