A spectrophotometric study of trivalent actinide complexes in solutions—III[1]

Hydrothermal synthesis, structural, Raman, and luminescence studies of Am[M(CN)2]3·3H2O and Nd[M(CN)2]3·3H2O (M=Ag, Au): Bimetallic coordination polymers containing both trans-plutonium and transition metal elements

“…In this region, americium luminescence spectar are known of overlapping emissions originating from two different excited levels [52][53][54][55][56][57][58][59]. Based on the established assignments, the higher energy of the emission (with a maximum at 14350 cm À1 ) corresponds to the 5 D 1 0 -7 F 1' transitions [54][55][56][57][58][59], while the lower-energy side mainly corresponds to contributions from the 5 L 6 0-7 F 2 0 transitions. When compared with the americium iodates and borosilicate matrices reported earlier [60][61], the most intense band for the americium emission in the Am[Ag(CN) 2 ] 3 Á 3H 2 O system is red-shifted by 250 cm À1 .…”

Solubility of NaNd(CO3)2 · 6 H2O(c) in Concentrated Na2C03 and NaHC03 Solutions

“…For example, Silva and Nitsche [7] determined Am0H(C0 3 )(c) to be the stable solid phase in suspensions equilibrated with 0.03% C0 2 (pH about 6). Bemkopf and Kim [5] reported that Am0H(C0 3 )(c) was the thermodynamically stable solid phase in solutions with total carbonate concentrations of at least 0.1 M. However, Shiloh et al [6] found Am 2 (C0 3 ) 3 (s) to be the stable phase in 0.1 to 0.6 M K 2 C0 3 . More recently, Runde and Kim [8] reported NaAm(CO,) 2 (s) to be the stable solid phase in 5 M NaCl solution of neutral pH under 0.01 atm C0 2 partial pressure and Kim et al [9] used time-resolved laser-induced fluorescence spectroscopy to characterize europium(III) and curium(III) carbonate solids and their aqueous carbonato complexes in 0.1 M NaC10 4 solutions, with pH from 4 to 10 and under 1 to 100% C0 2 partial pressure.…”

“…In recent years, the solid-liquid phase equilibria of trivalent actinides and lanthanides in carbonate-bicarbonate systems have been the subject of several studies because of the following concerns: 1) some natural aqueous systems have high C0 2 partial pressures (0.03 to 10%) [1,2], which results in high aqueous concentrations of carbonate and bicarbonate, and 2) actinide and lanthanide cations form strong aqueous carbonato complexes under certain conditions [3][4][5][6], which could increase the aqueous concentrations of these cations and significantly enhance their mobility.…”

Thermodynamics of Cm(III) in Concentrated Electrolyte Solutions. Carbonate Complexation at Constant Ionic Strength (1 m NaCl)

“…In general, the formation of the complexes AnCOi, An(C0 3 ) 2 and An(C0 3 )^ (An = actinide) in carbonate media is reported. For Am(III), mixed hydroxo-carbonate [6,19,20] and bicarbonate complexes [6] have been also proposed. However, the ΝΕΑ Thermodynamic Data Base review on Am(III) concluded that the formation of these complexes has not been clearly demonstrated [5].…”