Vibrational spectroscopic investigations of some Hofmann-Td-type complexes: Ni(2-(1-cyclohexenyl)ethylamine)2M(CN)4 (M = Cd or Hg)

New Hofmann-Td- type complexes in the form of Ni(CyHEA)2M(CN)4 (where CyHEA = 2-(1-cyclohexenyl)ethylamine and M = Cd or Hg) have been prepared in powder form and their infrared (4000–100 cm−1) and Raman (2800–1650 cm−1) spectra have been reported. The thermal behaviour of these complexes has been investigated by differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA). The results suggest that these compounds are similar in structure to the Hofmann-Td-type complexes.