A spectrophotometric study of trivalent actinide complexes in solutions-III[1]. Americium with bromide, iodide, nitrate and carbonate ligands[2]

The light absorption spectra of americium(III) in concentrated aqueous lithium bromide, iodide and nitrate, magnesium iodide, potassium carbonate and nitric acid have been obtained, together with those of extracts into triisooctylammonium nitrate solutions in xylene. Effective stability constants for the first (inner sphere) complex are, log β₁^* = -1·3 ± 0·1 for AmNO₃²⁺ and -3·3 ±0·1 for AmBr²⁺; the iodide complex is much weaker than the latter. Solubility studies show that [Am(OH)(CO₃)₃]^4- exists in 0·1-0·6 M potassium carbonate solutions. The spectral changes are discussed in terms of the environmental effects on the 5f-5f transitions in americium(III).