New Np(VI) and Pu(VI) dimolybdates Rb2NpO2(MoO4)2·H2O (I), Cs2NpO2(MoO4)2·H2O (II), Cs2PuO2(MoO4)2·H2O (III), and Rb2PuO2(MoO4)2·H2O (IV) were synthesized under hydrothermal conditions. The crystal structures of the compounds were determined, and their absorption spectra in the UV, visible, and IR ranges were measured. The compounds crystallize in the monoclinic system. Their crystal structure is based on [AnO2(MoO4)2]n2n– anionic layers (An = Np, Pu) formed by (AnO2)O5 pentagonal bipyramids and MoO4 tetrahedra, sharing common vertices. Each An atom in the layer is bonded to other five An atoms via MoO4 tetrahedra with the formation of a 43432 network. The effect of the ionic radius of the outer-sphere cation on the parameters of the crystal structure and features of the absorption spectra is discussed. 相似文献
Oxidation of Cr(III) hydroxides, double Fe(III)-Cr(III) hydroxides, and some examples of spinel phases NiCr2O4 and Fe(Cr,Fe)2O4 in alkaline suspensions (0.2-0.5 M NaOH) under the action of air and pure oxygen (1-3 atm) was studied. The reaction rate increases with increasing concentration of alkali, temperature, and oxygen pressure. Under these conditions, Pu(IV) sorbed on chromium hydroxides is not oxidized with oxygen and remains in the precipitate. 相似文献
The compounds NH4[AnO2(C6H4FCOO3], where An = U (I), Np (II), or Pu (III), CgH4COO? is the 2-fluorobenzoate anion, were synthesized and studied by single crystal X-ray diffraction. Compounds I–III are isostructural and crystallize in the cubic system, space group P213, Z = 4. The main structural units of I–III are mononuclear complexes [AnO2(C6H4COO)3]? belonging to crystal-chemical group AB31 (A = AnO22+, B01 = C6H4FCOO?). The actinide contraction in the structures of I–III is manifested in a regular decrease in the lengths of the An=0 bonds in the AnO22+ cations and in the volumes of the Voronoi-Dirichlet polyhedra (VDPs) of the An atoms in the series U-Np-Pu. The intermolecular interactions in crystal structures of I–III were analyzed by the method of molecular VDPs.
Complexation of methanesulfonic acid with Np(IV), Np(V), and U(VI) ions in aqueous solutions was studied. New crystalline
compounds HImid[Np(C2O4)(CH3SO3)3(H2O)2] (I), [NpO2(Terpy)(CH3SO3)·(H2O)]·2H2O (II), and [UO2(CH3SO3)2(H2O)] (III) were isolated. The absorption spectra of all the compounds in the IR, visible, and UV ranges were examined. The relationship
between the composition, crystal structure, and IR and electronic absorption spectra of the complexes is discussed.
Original Russian Text ? G.B. Andreev, N.A. Budantseva, I.G. Tananaev, B.F. Myasoedov, 2009, published in Radiokhimiya, 2009,
vol. 51, no. 3, pp. 197–201. 相似文献
The behavior of Np in higher oxidation states in alkaline solution containing silicate and aluminate ions was studied. In formation of a crystalline aluminosilicate in a solution, Np(V), (VI), and (VII) are not incorporated into its crystal structure but hamper formation of the solid phase. The possibility of sorption of Np on various aluminosilicates is primarily governed by its oxidation state. Np(V) and Np(VII) are not sorbed from strong alkali. Np(VI) is retained by aluminosilicate materials to various extents depending on the surface characteristics and surface area of these materials. On heating, the degree of Np(VI) sorption decreases, which suggests the physical nature of the process. 相似文献
As a result of Np(V) glycolate reaction with 2,2′-bipyridyl, the novel coordination polymer [NpO2(C2O3H3)(Bipy)] · 2.5H2O was formed. The structure consists of infinite chains of [NpO2(C2O3H3)(Bipy)] and water molecules. The crystal structure is confirmed by IR and UV–vis spectroscopic data. This complex is the first example of An glycolate with neutral molecular ligand. 相似文献
A new Np(IV) complex, [N(CH3)4]4[Np(NCS)8], was prepared. Its crystal structure was determined, and the absorption spectra in the IR and near IR ranges were measured. Crystal data: a = 27.280(6), b = 12.288(3), c = 13.493(3) Å, space group Pna21, Z = 4, V = 4523(2) A3, R = 0.044, wR(F2) = 0.091. The crystal structure of the compound consists of [Np(NCS)8]4- anions and N(CH3)4+ cations. The coordination polyhedron of the Np atom is a distorted tetragonal antiprism formed by the nitrogen atoms of eight NCS- ions. 相似文献
A new complex compound of U(VI) with m-hydroxybenzoic acid, K[(UO2)(C7H5O3)3]·5H2O, was prepared and characterized. A single crystal X-ray diffraction study showed that the coordination polyhedron of the
U atom is a hexagonal bipyramid whose equatorial plane is formed by the O atoms of carboxy groups of three anions of m-hydroxybenzoic acid. The K atoms act as outer-sphere cations linking the adjacent anions [UO2(C7H5O3)3]− into neutral dimers {[UO2(C7H5O3)3]K(H2O)3}2. The structure also contains water molecules of crystallization, retained by hydrogen bonds. 相似文献
Behavior of Pu(VI) in the course of crystallization of aluminosilicate in 2 and 3 M NaOH was studied. Plutonium(VI) inhibits aluminosilicate crystallization. At the Al : Si : Pu molar ratio of 10 : 40 : 2 in the initial mixture, only a minor amount of the X-ray amorphous phase is formed. Partial sorption of Pu(VI) on the aluminosilicate precipitate depends on the alkali concentration in the solution. As determined by spectrophotometry, only neutral and low-charged Pu(VI) hydroxo complexes are sorbed on the aluminosilicate; anionic complexes like [PuO2(OH)4]2- formed in more alkaline solutions are not sorbed. Plutonium(IV) formed by reduction of Pu(VI) is sorbed on aluminosilicate from 3 M NaOH. 相似文献
Previously unknown arsenates of hexavalent U, Np, and Pu, (H3O)[(UO2)(AsO4)]·3H2O (I), (H3O)· [(NpO2)(AsO4)]·3H2O (II), and (H3O)[(PuO2)(AsO4)]·3H2O (III), were synthesized under hydrothermal conditions. The crystal structure of the compounds was determined, and their absorption spectra were measured. The compounds crystallize in tetragonal space group P4/nmm. 相似文献