Vibrational study of (CH<inf>3</inf>NH<inf>3</inf>)<inf>2</inf>ZnCl<inf>4</inf> and (CH<inf>3</inf> NH<inf>3</inf>)<inf>2</inf>ZnBr<inf>4</inf>

Raman and infrared spectral studies of (CH3NH3)2ZnCl4 and (CH3NH3)2ZnBr4 were carried out at 90, 300 and 443 K. The vibrational spectra were analysed on the basis of the C 524 space group. Assignments were also made by comparison with the spectra of the N‐deuterated analogues. The non‐degenerate CN stretching mode showed splitting due to non‐equivalent cations in the lattice as opposed to layer type of perovskites. Above 426 K, these splittings are absent, indicating the removal of non‐equivalence. The cation bands are broad above 426 K, indicating the reorientational motion of the cations. Copyright © 1992 John Wiley & Sons, Ltd.