The stability of tetravalent berkelium in acid solution and the absorption spectra of Bk(IV) and Bk(III)

Abstract

The stability of Bk(IV) in sulfuric acid solutions was studied as a function of acid strength. To obtain the rate of reduction due to radiolysis, the absorption spectra were observed over a period of time. The dominant spectral feature of Bk(IV) in sulfuric acid is a strong charge-transfer band centered at 290 nm. The rate of reduction was inversely proportional to the acidity and closely paralleled the efficiency of production of H 2O 2 in that medium. The half-times ranged from 2·1 to 16·7 hr for 0·05M-4·5M H 2SO 4 solutions. The stability of Bk(IV) in perchloric acid and in sodium pyrophosphate solutions was also investigated. Observations of the spectrum of Bk(III) were extended further into the ultraviolet to 200 nm and yielded nine new bands. Four strong bands are believed to be due to allowed transitions, placing the lowest level of the 5f 76d configuration at 41,300 cm −1.