Ultraviolet–Visible Diffuse Reflection Investigation of the Thermal Decomposition of Samarium Trichloride Hexahydrate

Abstract

The thermal decomposition of the hexahydrate of samarium trichloride under an air atmosphere and under low pressure has been monitored through the use of ultraviolet–visible (UV-vis) diffuse reflection spectroscopy. The unique ability of lanthanide spectroscopy to investigate the near environment surrounding the samarium ion allowed for the identification of the hexa-, penta-, tetra-, tri-, di-, and monohydrates in both cases, as well as the formation of samarium oxychloride formed as the final decomposition product. The decomposition temperatures and the products observed in this report are compared to those obtained by other thermal and iso-thermal analyses of this compound, as well as the analogous decomposition of europium trichloride hexahydrate. Structural and environmental variations associated with the compounds, as indicated by the reflectance spectra, are discussed.