Abstract
Perovskite type layer-structure compounds of the formulas (Cn H2n+1 NH3)2·MCl4 and NH3 (CH2)n NH3MCl4 (M = Cd, Mn, Cu, Fe, n = 1–18) exhibit a variety of structural phase transitions which are connected with the dynamics of the alkyl-ammonium or alkylenediammonium chains respectively. Two classes of phase transitions have been observed; Order-disorder transitions of the rigid hydrocarbon chains and conformational transitions of the chains. Typical examples of both classes are presented and their chain dynamics are discussed.