Synthesis and Properties of Uranium Compounds (). Salts of Bis(undecatungstophosphato)uranate() Anion, [U(PW11O39)2]10-

摘要

A guanidinium salt of [U(PW11O39)2]10-, the solubility of which is adequate for crystal growing, has been synthesized. Using this salt or potassium salt, we have measured the stability of [U(PW11O39)2]10- as a function of pH of the solution and found that the anion is stable for the pH range 3~7. We have developed a colorimetric method for determining the concentration of U4+. In this method PW11O397- is added to U4+ in such a quantity that the mole ratio PW11O397-/U4+ exceeds 2 and the intensity of the 22.7kK band (￥? 1030 M-1cm-1) is measured. In order to develop a continuous method to recover uranium, we have determined the amount of recoverd PW11O397- after decomposing [U(PW11O39)2]10- by adding either a base or an oxidizing agent. The percentage of PW11O397- recovered was approximately 70% when a base was used and approximately 80% when K2S2O8 was used. A colorimetric method for determining PW11O397- has also been developed.