Estimating the stabilities of actinide aqueous species. Influence of sulfoxy-anions on uranium(IV) geochemistry and discussion of Pa(V) first hydrolysis

Abstract

Qualitative chemical information is used as a guideline for correlations between equilibrium constants or between equilibrium constants and atomic charges (deduced from quantum mechanics calculations). Pa(V) and Nb(V) hydrolysis constants are also recalculated from experimental data. log K3 Þ; and 10:0 5 AE 0:8 8 ðHPO 2À 4 Þ are estimated based on the trend of affinity for An cations in the series CO 2À 3 > HPO 2À 4 zSO 2À 3 > SO 2À 4 zS 2 O 2À 3 : These ideas and values are used to discuss U(IV) chemistry in S-containing ground-waters.

Formation of CaSO4(aq) and CaSeO4(aq) studied as a function of ionic strength and temperature by CE

“…This approach was originally proposed by Ciavatta [34] and can be used to calculate e Na þ ;SO (251C) were also extrapolated to zero ionic strength extrapolating the constants determined at different temperatures to zero ionic strength using Eqs (13) and (14) ¼ 0:23). This is consistent with correlations, which have been proposed for complexes of heavier trivalent and tetravalent hard cations with various bidentate oxyanions, which involve ionic bonds [38]. The formation constants of 1:1 complexes (namely log 10 K 0 ) can be correlated with the pKa 0 of the protonated oxyanions: the weaker is the acid, the stronger is the complex.…”

Precipitation of and compounds from aqueous solutions for and

“…The NH 4 LnðCO 3 Þ 2 ; xH 2 O compounds have their own behaviour which seems close to that of CsLnðCO 3 Þ 2 ; xH 2 O compounds. Those two mono-cations often have similar behaviours [2]. Runde et al assigned the most intense peak, i.e.…”

“…Such analogies are typically used to estimate unknown stability constants for their aqueous complexes and solid compounds, assuming they have the same stoichiometries [1,2]. However, this type of analogy is still discussed for the aqueous carbonate complexes of lanthanides (Ln) or actinides (An) in the þ3 oxidation state in concentrated solutions.…”

Characterization and remediation of soils contaminated with uranium

“…Some characteristics of uranium compounds, most of them determinant for choosing the remediation technique, are summed up in Table 4 [4,37,61,71,[112][113][114][115][116][117].…”