X-Ray Diffraction Study on the Incommensurate-Commensurate Phase Transition in {N(CD₃)₄}₂CoCl₄

Abstract

The space groups of six phases of {N(CD₃)₄}₂CoCl₄ were determined by X-ray diffraction as Pmcn(Z=4), incommensurate, P2₁cn(Z=20), P112₁⁄n(Z=12), P12₁⁄c1(Z=4) and P2₁2₁2₁(Z=12), respectively in the order of decreasing temperature. The deuteration causes the increase of the modulation wavenumber. This increase of the wave number agrees qualitatively with that expected from the distribution of modulation wavenumber in the reduced p-T phase diagram.