title: Role of anions and reaction conditions in the preparation of uranium(VI), neptunium(VI), and plutonium(VI) borates.
abstract: U(VI), Np(VI), and Pu(VI) borates with the formula AnO(2)[B(8)O(11)(OH)(4)] (An = U, Np, Pu) have been prepared via the reactions of U(VI) nitrate, Np(VI) perchlorate, or Pu(IV) or Pu(VI) nitrate with molten boric acid. These compounds are all isotypic and consist of a linear actinyl(VI) cation, AnO(2)(2+), surrounded by BO(3) triangles and BO(4) tetrahedra to create an AnO(8) hexagonal bipyramidal environment. The actinyl bond lengths are consistent with actinide contraction across this series. The borate anions bridge between actinyl units to create sheets. Additional BO(3) triangles and BO(4) tetrahedra extend from the polyborate layers and connect these sheets together to form a three-dimensional chiral framework structure. UV-vis-NIR absorption and fluorescence spectroscopy confirms the hexavalent oxidation state in all three compounds. Bond-valence parameters are developed for Np(VI).
authors.affiliation: Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States.
authors.forename: Shuao
authors.initials: S
authors.lastname: Wang
authors.forename: Eric M
authors.initials: EM
authors.lastname: Villa
authors.forename: Juan
authors.initials: J
authors.lastname: Diwu
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Alekseev
authors.forename: Wulf
authors.initials: W
authors.lastname: Depmeier
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt
mesh_terms: D000838:Anions / Q000737:chemistry; D001881:Borates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009405:Neptunium / Q000737:chemistry*; D011005:Plutonium / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry*
chemical_list: D000838:Anions; D001881:Borates; D014501:Uranium; D011005:Plutonium; D009405:Neptunium