The infrared and Raman spectra of matrix isolated binary and mixed mercury halides

Raman and ir spectra in the stretching region of all HgX2 and HgXY molecules (X,Y=Cl, Br, I) trapped in solid Kr at 20 °K are reported. Bands are assigned to modes of monomers and dimers. Bond stretching and interaction force constants are calculated and compared. The possibility of a slightly bent structure for several monomers is indicated. The dimer structure is shown to be centrosymmetric in all cases and the identity of the bridged halogen is suggested for the ’’mixed’’ dimers.