THE PHOSPHATE COMPLEXATION OF NEPTUNIUM(V)

Authors
MORGENSTERN A KIM JI
Citation
A. Morgenstern et Ji. Kim, THE PHOSPHATE COMPLEXATION OF NEPTUNIUM(V), Radiochimica Acta, 72(2), 1996, pp. 73-77
Citations number
15
Categorie Soggetti
Nuclear Sciences & Tecnology","Chemistry Inorganic & Nuclear
Journal title
Radiochimica Acta → ACNP
ISSN journal
00338230
Volume
72
Issue
2
Year of publication
1996
Pages
73 - 77
Database
ISI
SICI code
0033-8230(1996)72:2<73:TPCON>2.0.ZU;2-C
Abstract
The phosphate complexation of Np(V) is investigated in the pH range fr om 6.4 to 10.0 in 0.1 M NaClO4 at 22+/-2 degrees C by absorption spect roscopy. The formation of two phosphate complexes is confirmed by spec troscopic speciation: NpO2HPO4- at 988.8 nm and NpO2PO42- at 993.6 nm with molar extinction coefficients of 251+/-8 and 201+/-11 I/mol cm, r espectively. The complexation constants are determined to be log beta = 2.54+/-0.02 for NpO2HPO4- and log beta = 6.33+/-0.08 for NpO2PO42-. The competition of the phosphate complexation with the carbonate compl exation is demonstrated by speciation calculation under different geoc hemical conditions.