Crystal structure and phase transition of single crystalline CsNH _2SO_3

摘要

Differential scanning calorimetry (DSC) and X-ray diffraction measurements have been performed on cesium sulfamate CsNH_2SO_3 single crystal. Two distinct endothermic peaks in the DSC curves are observed at 330 and 436 K. It is pointed out that the peak at 330 K is attributed to the structural phase transition, and the other peak at 436 K is associated with the thermal decomposition of the crystal. The structures in room- and high-temperasture phases are determined, and the space group of the sample crystal is found to change from monoclinic P 2_1/c to orthorhombic Pnma. The structure of the room-temperature phase consists of two different types of N-H?O hydrogen bond, but in the high-temperature phase there is no specific hydrogen bond between the NSO_3 pseudo-tetrahera.