Incommensurate-Commensurate Phase Transition of {N(CH₃)₄}₂MnCl₄

Abstract

By means of X-ray diffraction study, an incommensurate phase of {N(CH₃)₄}₂MnCl₄ was found in the temperature range of 19.1∼18.5°C. Incommensurate satellite reflections were observed at (h 0 l±ζ) with ζ\simeq0.483. In the temperature range of 18.5∼−6.5°C, the value of ζ is (Remark: Graphics omitted.) (commensurate). This phase is ferroelastic and monoclinic with the unique axis parallel to the a-axis. Below −6.5°C, another monoclinic phase (P112₁⁄n) with (Remark: Graphics omitted.) appears.