Ma J, Yang C, Han J, Yu J, Hu S, Yu H, Long X. Density Functional Theory Investigations on the Mechanism of Formation of Pa(V) Ion in Hydrous Solutions.
Molecules 2019;
24:E1169. [PMID:
30934559 PMCID:
PMC6471942 DOI:
10.3390/molecules24061169]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 11/16/2022] Open
Abstract
Due to the enormous threat of protactinium to the environment and human health, its disposal and chemistry have long been important topics in nuclear science. [PaO(H₂O)₆]3+ is proposed as the predominant species in hydrous and acidic solutions, but little is known about its formation mechanism. In this study, density functional theory (DFT) calculations demonstrate a water coordination-proton transfer-water dissociation mechanism for the formation of PaO3+ in hydrous solutions. First, Pa(V) ion preferentially forms hydrated complexes with a coordination number of 10. Through hydrogen bonding, water molecules in the second coordination sphere easily capture two protons on the same coordinated H₂O ligand to form [PaO(H₂O)₉]3+. Water dissociation then occurs to generate the final [PaO(H₂O)₆]3+, which is the thermodynamic product of Pa(V) in hydrous solutions.
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