Investigation of thorium hydroxopropionates

The article presents the results of an investigation of processes of precipitation of thorium hydroxopropionates in the system Th(NO3)4-HNO3-C2H5COOH-NH4OH-H2O. Basic thorium propionates with compositions Th(OH)(C2H5COO)3.4H2O; Th(OH)2(C2H5COO)2.H2O and Th(OH)3(C2H5COO).4H2O were isolated. Their thermal stability was studied, and the density of the crystals was determined. It was shown that when ammonia is added, the thorium content in solution at first decreases as a result of the liberation of the compounds found - thorium monohydroxopropionate and dihydroxopropionate - then (at pH=4.2-6.6) increases appreciably, probably in connection with the formation of a soluble complex (NH4)2Th(C2H5COO)6. When ammonia is further added (pH>6.7), the thorium content again decreases substantially (to approximately 1 mg/liter at pH=9.8) in connection with the formation of products of profound hydrolysis of thorium propionate