Precipitation and Hydrolysis of Thorium in Aqueous Solution. IV. Studies of the Systems: Thorium Nitrate-Sodium Fumarate and Thorium Nitrate-Potassium Maleate

Precipitation of thorium from aqueous solutions of thorium nitrate and sodium fumarate and potassium maleate respectively has been investigated for a broad range of concentrations of preci~ pitation components and pH. From the results of chemical analyses and from the DT A and IR spectra the most probable formulas of the formed precipitates are: Th(H-fumarate)2 (0H)2 X 5 H 20 and [ g~ Thg~ (Mal Th g~ )4] X 6 H20. In the soluble mixed hydroxo maleato thorium complex, which is in equilibrium with thorium hydroxide, probably three hydroxide ions are bound to one thorium. It has been found that with fumarate ion thorium does not form a soluble complex