The results of Raman and infrared investigations of the spectra of Co²⁺ ions in CsCdCl₃ and CsMgCl₃are reported. These ions substitute for the divalent cations in these double chlorides and experience a trigonal crystal field which splits the four spin-orbit levels of the 4Tlg(⁴F) ground manifold into six Kramers doublets with energies lying within 0 – 1400 cm-¹. Electronic transitions within this ground term have been observed and are satisfactorily fitted using the complete 3d⁷ configuration crystal field matrices. Zeeman-Raman and – infrared experiments on CsCdCl₃:co and CsMgCl₃:Co have been performed and yield g values for the excited electronic states. These excited state g values are also calculated using crystal field theory and are in good agreement with those obtained experimentally. Selection rules governing the occurrence of the electronic Zeeman transitions are derived for the appropriate cobalt ion site symmetries and are in agreement with the results. The Raman and infrared spectra of Co²⁺ ions in CsCdCl₃ and KCdCl₃ are measured and are presented, together with the results of optical studies of Co²⁺ ions in CsCdCl₃. A preliminary investigation of the electronic transitions of Fe²⁺ ions in CdCl₂-type crystals has been carried out using Raman and infrared spectroscopy. The spectral data, together with a tentative analysis, are presented.