Refinement of crystal structure of tri-glycine sulfate

Abstract

In 1959 crystal structure of tri-glycine sulfate (abbreviated as TGS) was analysed with X-rays by Hoshino et al.1 The reported value (0.167) of the discrepancy factor R, however, seems to be a little too large to discuss in detail the nature of the ferroelectric phase transition of TGS. Neutron diffraction studies also were made2 to determine hydrogen positions around 1959, but the least squares calculations were not converged and conclusive results were not obtained. Since then the question has been whether or not the large value of R and difficulties encountered in the neutron studies were caused by the disordered structure3 of TGS at room temperature. This question was expected to be answered by collecting very accurate X-ray data. Studies have been made along this line. This short communication is to report briefly our results hitherto obtained.