Synthesis of the Modifications of Ca2SiO4 and the Determination of their Powder X-ray Diffraction Patterns

The high temperature modifications of Ca2SiO4, free from stabilizers, cannot be quenched to room temperature, and the high temperature X-ray diffractions of the modifications, reported by many authors, are obscure, and cannot be analyzed. On the other hand, the powder X-ray diffractions of many minerals, natural and synthetic, reported as solid solutions of the respective modifications, do not coincide each other.In the previous paper, the authors reported the high temperature X-ray diffractions of pure Ca2SiO4 over the temperature range from 25° to 1550°C, which were sharp enough to be detected the characteristic profile of the each modification.In this paper, the authors report the more precise powder X-ray diffractions of the modifications quenched to room temperature and adding suitable stabilizers, which are usually contained as miner components in commercial portland cement clinkers. The diffraction patterns of the samples coincide to that of high temperature X-ray diffractions of the each modification, and the intensity and the spacing of the diffractions fully coincident to the structure factor (F hkl) and the spacing (d hkl) respectively, calculated from the each structure model, assumed by isomorphic studies of M. A. Bredig.From this study, the powder X-ray diffractions of each modification are reliably determined, and the assumptions on the crystal structures are justified.