Spectroscopic investigation of some halide and mixed-halide complexes of zinc(II), cadmium(II) and mercury(II) with piperidinium and morpholinium cations.

The conductivities and IR spectra (4000-60 cm-1) of some complex halides of general formula A2MX4, A2MX2Y2 and ACdCl3 (A = piperidinium and morpholinium cation; M = Zn, Cd and Hg; X ? Y = Cl, Br and I) have been examined. The stereochemistry of the anions is inferred from the M-X frequency assignments. All the complexes tend to be tetrahedral and a lowering in Td symmetry is found in the morpholinium compared with the piperidinium complexes, owing to strong ionic interactions due to hydrogen bonds. In the CdCl3 - complexes the presence of bridge Cd-Cl vibrations, while in the mercury complexes the presence of terminal and bridge Hg-Cl vibrations, suggest the formation of dimeric or polymeric species