Observations on the systems Th-S, Th-Se and Th-Te

Abstract

A reinvestigation of these systems has indicated the marked effect of the purity of materials on the phases formed. New polychalcogenides have been found (ThS_2.5, and ThSe_2.5 having tetragonal symmetry, and ThTe₃ monoclinic), as also has a sesquitelluride (Th₂Te₃, with hexagonal symmetry) which is probably non-stoichiometric. Discrepancies between the present results and those of previous workers are discussed.