Crystal Structure of CsH₃(SeO₃)₂at Low Temperature Range

Abstract

The crystal of CsH3(SeO3)2 was confirmed to be triclinic system with the space group P and to have a superlattice structure below the antiferroelectric phase transition temperature (TN = 149 K). The crystal structure was studied at 103 K below TN by means of the single crystal x-ray diffraction. The final discrepancy factor was reduced to 0.0645. The structure analysis pointed out that all possible positions of atoms are in the ordering state below TN. In order to ascertain the antiferroelectric state in the low phase, the pseudo-moments proportional to the displacements are assumed as the dipole moment of SeO3 tetrahedron.