X-Ray Studies of the Successive Structural Phase Transitions of (CH₃)₃NHCdCl₃

Abstract

The successive structural phase transitions in a linear chain compound (CH 3 ) 3 NHCdCl 3 were investigated by an X-ray photographic method. From the intensities of the super lattice reflections, the structures of the monoclinic (3×2) phase which has P2 1 /m symmetry and the hexagonal (3×3) phase which has P6 3 /m symmetry were discussed. Present analysis shows that the phase transitions of this compound are fairly well described by a sequence of rigid reorientations of the metal-chlorine chains. It was also argued that the (3×3) phase would be composed of micro twins.