Novel heptavalent actinide compounds: tetrasodium dihydroxidotetraoxidoneptunate(VII) hydroxide dihydrate and its plutonium analogue
Mikhail S. Grigoriev, e-mail: [email protected]
Abstract
The title compounds, Na4[NpO4(OH)2]OH·2H2O and Na4[PuO4(OH)2]OH·2H2O, are isostructural and isomorphous, and contain complex [AnO4(OH)2]3− anions (Ac is an actinide) in the form of distorted tetragonal bipyramids, Na+ cations, crystallization water molecules and outer-sphere OH groups. The complex [AnO4(OH)2]3− anions occupy general positions and the coordinated OH groups deviate significantly from a centrosymmetric relative orientation. The [AnO4(OH)2]3− anions exhibit anisotropic actinide contraction; the shortening of the An—O(hydroxide) bonds on going from Np to Pu is greater than that of the AnO4 groups.
