GB804311A - Uranium hexachloride and processes of producing the same - Google Patents

Abstract

Uranium hexachloride is prepared by heating uranium pentachloride under sub-atmospheric pressure to a temperature between 80 DEG and 180 DEG C. whereby the uranium pentachloride is split into uranium tetrachloride and hexachloride, the latter subliming on to a cooled surface. As shown in the Figure, a molecular still consists of an outer wall 11 the lower portion of which is contained in a sand bath 19, and an inner vessel 18 which is filled with liquid oxygen. The space between the two vessels is evacuated through line 21 to a pressure between 10-6 and 10-3 mm. of mercury. The charge of uranium pentachloride 17 is placed in the bottom <PICT:0804311/III/1> of the vessel 16 and after reduction of pressure the sand bath is heated to a temperature between 80 DEG and 180 DEG C. and the wall of the vessel 18 is cooled to a temperature below 10 DEG C. by means of the liquid oxygen contained therein. Uranium hexachloride sublimes and condenses on the wall 18 and the residue consists of uranium tetrachloride. The product UCl6 is a finely crystalline iridescent green substance having a vapour pressure of about 1.3 mm. of mercury at a 100 DEG C.; it is extremely hydroscopic and unstable in ordinary atmospheres, wherein it decomposes to UO2Cl2. It is therefore necessary that the still be opened in an inert dry atmosphere. Specification 800,731 is referred to.