Thorium dioxide, combination with

Thorium sulfide, ThSz, is obtained by the action of H2S or sulfur on thonum metal. The oxysulfide, ThOS. has been obtained in several ways, one of which is by the action of CS2 on thorium dioxide at elevated temperatures. At 800°C and under pressure, sulfur combines with thonum to yield compounds with approximately die formulas ThS, TI12S3, and TI13S7 The first two have semimetallic properties and may be employed as ceramics for use with highly electropositive metals, whereas the last appears to be a poly sulfide. 

The method described below for the preparation of thorium bromide combines the method of Troost and Ouvrard3 with that of Moissan and Martinsen.2 The former passed bromine over a heated mixture of thorium dioxide and carbon but did not purify the thorium bromide formed. The latter prepared the halide by the action of bromine on heated thorium carbide and purified the product by sublimation, first in a current of hydrogen and... 

The Th-0 system was studied by investigating the vaporisation behaviom of the dioxide phase and the univariant system, Th(l) + Th02(cr). A combination of mass effusion and time-of-flight mass-spectrometric techniques was employed to yield an internally consistent set of thermodynamic data. The thorium used was crystal-bar material with fewer than 200 ppm total impurities, which was also used for the preparation of Th02(cr). 

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