Thorium Silicide, ThSi₂

Thorium Silicide, ThSi₂, is prepared by heating in a magnesia crucible, to 1200° C., an intimate mixture of 15 grams potassium thorifluoride, 60 grams potassium silicifluoride, and 50 grams aluminium, the product being freed from aluminium and silicon by treatment with potassium carbonate solution. It may also be prepared by heating a mixture of thoria and silicon in an electric furnace, or by heating a mixture of aluminium, silicon, and thorium to 1000° C. It forms quadratic plates, resembling graphite, and has a density of 7.96 at 16° C. It is soluble in aqueous mineral acids, but not in aqueous alkalis.