最大酸化状態のアクチノイド(Ac-U)を含むアクチノイドフッ化物錯体の結合モチーフの特性評価:電子構造理論を用いて
Kayleigh R Autry1, Jackson W Maxwell1, David A Dixon1
1Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States.
Abstract:
Density functional theory (B3LYP) and correlated molecular orbital theory (CCSD(T)) calculations were used to predict the properties of novel actinide-fluoride complexes formed by the addition of a fluorine to AnFn compounds, with actinides in their normal maximum oxidation state (n), leading to the formation of an ion-pair complex [AnFn-1+][F2-] for the earlier actinides (Ac, Th, and Pa). UF7 prefers a structure with a weakly associated fluorine, forming a [UF6][F•] complex, likely due to steric hindrance. Ionization of [AnFn-1+][F2-] forms a weakly bound [AnFn-1+][F2] complex. Ionization of AnFn leads to the formation of [AnFn-22+][F2-] complex so that the electron is not removed from the actinide and maintains the An oxidation state. The ionization energies, An-F bond dissociation energies, and enthalpy for the loss of F20/- of these complexes are in agreement with the available experimental data. The fluoride affinities of AnFn and the electron affinities of AnFn+1 were calculated. The fluoride affinities are large and comparable to those of AsF5 and SbF5 so they are strong Lewis acids. The electron affinities are sizable, indicating that AnFn+1- will be powerful oxidizing agents and should be considered in models of molten salt reactors when fluoride is present.
関連する概念動画
Valence Bond Theory
Valence Bond Theory
Ionic Bonding and Electron Transfer
Covalent Bonding and Lewis Structures
VSEPR Theory and the Basic Shapes
Oxidation Numbers


