TRANSFORMATION OF CHERNIKOVITE INTO META-URANOCIRCITE-II, BA(UO2)2(PO4)2 6H2O AND STUDY OF ITS SOLUBILITY

Chernikovite, (H3O)2(UO2)2(PO4)2, was synthesized and subsequently transformed into metauranocircite II, Ba(UO2)2(PO4)2.6H2O, by ion-exchange experiments. The crystals are lemon-yellow and strongly fluorescent. From solubility data a mean pK(s) value at 25-degrees-C was determined as 51.79 +/- 0.21. For a cell volume of 16.31.7 angstrom3 and Z = 4 the density was calculated as 3.970 g/cm3 whereas the measured density is 3.964 g/CM3. The X-rav powder pattern shows the following strongest lines: 3.609(60)(114), 3.47 (60)(123BAR), 2.9272(90)(132), 2.9006(90)(312BAR), 2.6065(80)(116BAR), 2.4581(75)(233BAR), 2.2015(100)(143 ; 143BAR), 2.1869(100) (241 ; 226 ; 241BAR).