Redox reactions for Group 5 elements, including element 105, in aqueous solutions

Abstract

Standard redox potentials Eo(Mz++X/MZ+) in acidic solutions for group 5 elements including element 105 (Ha) and the actinide, Pa, have been estimated on the basis of the ionization potentials calculated via the multiconfiguration Dirac-Fock method. Stability of the pentavalent state was shown to increase along the group from V to Ha, while that of the tetra-and trivalent states decreases in this direction. Our estimates have shown no extra stability of the trivalent state of hahnium. Element 105 should form mixed-valence complexes by analogy with Nb due to the similar values of their potentials Eo(M3+/M2+).The stability of the maximum oxidation state of the elements decreases in the direction 103 > 104 > 105.

Electronic structure theory of the superheavy elements

“…This analysis also gave the changes in the enthalpies and Gibbs free energies due to relativistic contributions in the MCSCF computations. Similar calculations were performed also for Db [138]. The stability of the pentavalent state was shown to increase along the group from vanadium to tantalum, while that of the tetra-and trivalent states decreases with increasing nuclear charge.…”

Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report)

“…It was shown that the stability of the pentavalent state increases from V to Db, while the stability of the tetra-and trivalent state decreases. Although it was found that the stability of the maximum oxidation state decreases in going from Lr to Db, no extra stability of the trivalent state in Db was found [116]. It would be interesting to test this prediction in reduction experiments similar to the experiments performed on Lr [117].…”

“…Differences between the chemical behavior of Db and the extrapolated properties of an eka-tantalum could result from a larger ionic radius, a different effective charge, and a different radial extension of the 6d orbitals, which are most important in its molecular bondings [100,[110][111][112][113][114][115]. Redox potentials were estimated for the group 5 elements, including the pseudohomolog Pa, on the basis of ionization potentials from MCDF calculations [111,116]. It was shown that the stability of the pentavalent state increases from V to Db, while the stability of the tetra-and trivalent state decreases.…”

Aqueous-phase chemistry of the transactinides

“…It was shown that the stability of the pentavalent state is increasing from V to Db, while the stability of the tetra-and trivalent state is decreasing. Although it was found that the stability of the maximum oxidation state decreases when going from element 103 to 105, no extra stability of the trivalent state in element 105 was found [121]. It would be interesting to test this prediction in reduction experiments similar to the experiments performed on element 103 [122].…”

“…Differences in the chemical behavior of element 105 to extrapolated properties of an eka-tantalum could result from a larger ionic radius, a different effective charge, and a different radial extension of the 6d orbitals which are most important in its molecular bondings (Pershina et al [113][114][115], Fricke et al [112], Pershina et al [116][117][118][119][120]). Redox potentials were estimated for the group-5 elements including the pseudo-homolog Pa on the basis of ionization potentials from MCDF calculations [112,121]. It was shown that the stability of the pentavalent state is increasing from V to Db, while the stability of the tetra-and trivalent state is decreasing.…”