Thermal expansion properties and hygroscopicity of Y2−x Sm x W3O12 (x = 0.0–0.4) compounds

A novel class of solid solutions of Y2−x Sm x W3O12 (x = 0.0−0.4) were synthesized and studied by means of powder X-ray diffraction. All samples crystallize in an orthorhombic space group Pnca. The lattice parameters a, b and c of Y2−x Sm x W3O12 increase with increasing Sm content. Since the compounds of this series hydrate at room temperature, thermogravimetric (TG) analysis was carried out. The result shows that the compound stores less water with increasing Sm content. The thermal expansion properties of Y2−x Sm x W3O12 (x = 0.1, 0.3 and 0.4) were investigated with high temperature X-ray diffraction. Negative thermal expansion coefficient α I becomes less negative from −6.644×10−6 to −6.211×10−6°C−1 when x changes from 0.1 to 0.4.