Hydrogen Peroxide in the Chemistry of f-Elements

• Published in: Radiochemistry (New York, N.Y.) N.Y.), 2024-06, Vol.66 (3), p.283-300
• Main Authors: Shilov, V. P., Fedoseev, A. M., Myasoedov, B. F.
• Format: Article
• Language: English
• Subjects: Acidic oxides; Actinides; Aqueous solutions; Charge exchange; Charge transfer; Chemical reduction; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Coordination; Hydrogen peroxide; Lanthanides; Neptunium; Nuclear Chemistry; Oxidation; Peroxides; Rate constants
• ISSN: 1066-3622; 1608-3288
• DOI: 10.1134/S1066362224030019

The properties of H 2 O 2 and its reactions with lanthanide and actinide ions are considered. The potential values of pairs involving H 2 O 2 in acidic and alkaline solutions are given. Depending on the oxidative potential of the f -element ion and pH, H 2 O 2 exhibits oxidizing or reducing properties. The kinetics and mechanisms of reactions of H 2 O 2 with lanthanides(II–IV) and with actinides(III–VII) in acidic, carbonate, and alkaline media have been analyzed. Ions of f -elements(III–VI) form peroxide complexes. The peroxo group occupies either one (OOH) or two (OO) coordination sites. U(VI), Np(IV) binds up to 3 peroxo groups. Oxidation or reduction reactions proceed intramolecularly. In the case of Yb 2+ , Sm 2+ , U 3+ , Ce 4+ (in an acid solution), Pr(IV) and Am(IV) (in a weakly acidic medium), the bimolecular rate constants are 10 5 – n × 10 6 L/(mol s), which exceeds the rate of ligand exchange in the coordination sphere of the f -element ion. Therefore, charge transfer occurs in the outer sphere. Coordination spheres of Ce(IV) oxalate, Tb(IV) with P 2 W 17 O 61 10– , and Np(VI) with NO 3 – slow down the charge transfer between H 2 O 2 and the f -element ion. H 2 O 2 arising during the radiolysis of aqueous solutions is in an excited state and is more active than H 2 O 2 introduced from the outside. Of particular interest are the reactions of H 2 O 2 with ions of f -elements in strongly complexing or nonaqueous (organic) media, as well as structural studies of solid compounds of peroxides of f -elements.