Collect. Czech. Chem. Commun. 1982, 47, 1269-1281

Ammonium uranyl carbonates - Complex compounds with variable coordination number?

Václav Baran

Nuclear Research Institute, 250 68 Řež


A series of ammonium uranyl carbonate (AUC) solid samples were prepared. Their chemical composition varied systematically and corresponded to the formula (NH4)x[UO2(CO3)y] with molar coefficients from x = 4.0 and y = 3.0 to 1.1 and 1.3, resp. The first samples of this series, with x in the range 4.0-2.7 and y in the range 3.0-2.3, revealed identical IR spectra as well as X-ray patterns, in contrast to the other ones. A reliable explanation of this fact is not at hand, one of the possibilities being the variable coordination number of the uranyl central ion. IR spectra of AUC and its sodium analogue were confronted, too, with the conclusion that architecture of both complexes is the same but with distinct quantitative differences.