A New Model for the Pollucite Thermal Expansion Mechanism

The thermal expansion behavior of cubic pollucite (CsAlSi2O6) in the temperature range 298 to 1473 K was investigated from the viewpoint of crystal structure, based on the model proposed in this study, with Rietveld analysis and high-temperature X-ray powder diffraction. Consequently, it has been found that the CsAlSi2O6 structure provides an enlargement-contraction mechanism for two kinds of rings, each composed of six (Si,Al)O4 tetrahedra in a three-dimensional aluminosilicate framework, in the temperature range 298 to 673 K.