Crystal structure of a double Np(V) and Co(NH3)63+ maleate, Co(NH3)6[NpO2(HL)2(H2O)3](HL)2?H2O [L = OOC(HC)2COO]

Crystal structure of a double Np(V) and Co(NH₃) ₆ ³⁺ maleate Co(NH₃)₆[NpO₂(HL)₂(H₂O)₃](HL)₂H₂O [L = OOC(HC)₂COO] was studied. The crystal structure consists of complex anions [NpO₂(HL)₂(H₂O)₃]^–, HL^– anions, [Co(NH₃)₆]³⁺ cations, and water molecules of crystallization. Hydrogen bonds in which proton donors are water molecules and hexaamminecobalt cations link structural fragments to form a 3D network. The coordination polyhedra of the Np(V) atoms are pentagonal bipyramids whose equatorial planes are formed by oxygen atoms of two HL^– anions and three water molecules. Four crystallographically independent maleate anions were identified in the structure. Two of these anions enter into the Np(V) surrounding, and their coordination capacity is 1.Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 521–523.Original Russian Text Copyright © 2004 by Charushnikova, Krot, Starikova.     

Synthesis and properties of Np(VI) and Pu(VI) monophthalates

Neptunium(VI) and plutonium(VI) monophthalates were prepared and characterized. The complexes AnO₂ (COO)₂C₆H₄ 2H₂O were isolated from cold solutions, and AnO₂ (COO)₂C₆H₄ 1.33H₂O, from hot solutions. NpO₂ (COO)₂C₆H₄ b. 2H₂O and PuO₂ (COO)₂C₆H₄ 2H₂O crystalize in the triclinic and monoclinic systems, respectively. The complexes AnO₂(COO)₂C₆H₄ 1.33H₂O are isostructural and crystallize in the rhombohedral system. The thermal behavior of these complexes was studied. Their IR and electronic absorption spectra were recorded. The properties of these complexes were compared to those of known U(VI) monophthalates.Translated from Radiokhimiya, Vol. 46, No. 5, 2004, pp. 389–395.Original Russian Text Copyright © 2004 by Krot, Bessonov, Grigorev, Charushnikova, Makarenkov.     

Crystal Structure of Neptunium(V) Phthalate (NpO2)2(OOC)2C6H4·4H2O

The crystal structure of (NpO₂)₂(OOC)₂C₆H₄·4H₂O [rhombic cell: a = 15.937(3), b = 26.922(5), c = 8.020(2) Å, space group Pbcn, Z = 8, V = 3441.0(12) ų, d _calc = 2.988 g cm^{- 3}, CAD4, MoK , graphite monochromator, 2934 independent reflections; R ₁ = 0.0352, wR ₂ = 0.0951] was studied. The structure consists of NpO₂ ⁺ cations, H₄C₆(COO)₂ ^{2 -} anions, and molecules of coordinated and crystallization water. The crystal lattice involves neutral layers [(NpO₂)₂(OOC)₂C₆H₄(H₂O)₃] _n parallel to the {101} plane. The dioxocations in these layers are bonded to each other to form cationic networks [the Np···Np distance is 3.911(1)-4.202(1) Å]. The coordination polyhedra of Np(1) and Np(2) are pentagonal bipyramids (CN 7). The point group of the neptunyl(V) groups is close to D _h. These groups are bidentate ligands in the cation-cation interaction. The Np = O bond lengths are 1.852(6) [Np(1)-O(1)], 1.849(7) [Np(1)-O(2)], 1.845(7) [Np(2)-O(3)], and 1.841(7) Å [Np(2)-O(4)]; the O = Np = O bond angles are 178.6(3)° [O(2)-Np(1)-O(1)] and 177.4(3)° [O(3)-Np(2)-O(4)]. The equatorial plane of the Np(1) bipyramid consists of two oxygen atoms of adjacent Np(2)O₂ ⁺ dioxocations, two water molecules, and a single oxygen atom of the phthalate anion. The equatorial plane of the Np(2) bipyramid consists of two oxygen atoms of adjacent Np(1)O₂ ⁺ dioxocations, two oxygen atom of the phthalate anion, and a single water molecule. The bond lengths in the equatorial plane of the bipyramid lie in the following ranges: Np-Oyl 2.373(7)-2.437(7) Å (average 2.397 Å) , Np-Ophth 2.360(7)-2.474(7) Å (average 2.431 Å), and Np-Owater 2.534(8)-2.558(9) Å (average 2.544 Å). The phthalate anions are tridentate bridging ligands binding neptunium atoms only within a single cationic network.     

Crystal Structure of Double Lithium Neptunium(V) Carbonate Dihydrate LiNpO2CO3·2H2O

According to the data of X-ray diffraction analysis, the structure of LiNpO₂CO₃·2H₂O is built of [LiNpO₂CO₃H₂O]_n layers, arranged perpendicularly to the [001] direction, and of crystallization water molecules. The layers are based on mixed cation-anion trigonal networks; Np(V) occurs in the hexagonalbipyramidal environment with three bidentate CO₃ ^{2 -} ions coordinated in the equatorial plane of the bipyramid. The coordination capacity of anions is 6 and 3 with regard to Np and Li, respectively.     

Synthesis and crystal structure of double Np(V) cesium oxalate CsNpO2C2O4 · nH2O

An X-ray diffraction study of CsNpO₂C₂O₄ · nH₂O was carried out. The structure consists of NpO ₂ ⁺ and Cs⁺ cations, oxalate anions, and water molecules. Dioxo cations are combined by cation-cation interaction into cyclic trimer in which each NpO ₂ ⁺ cation act as monodentate ligand. The coordination polyhedron of the Np(V) atom is a pentagonal bipyramid. The similarity of the structures of MNpO₂C₂O₄ · nH₂O (M = NH₄, Cs) based on cyclic trimers combined by oxalate ions into a three-dimensional framework was confirmed. Original Russian Text I.A. Charushnikova, N.N. Krot, I.N. Polyakova, 2006, published in Radiokhimiya, 2006, Vol. 48, No. 3, pp. 202–204.     

Nitrate Complexes of Neptunium(V) with Organic Single-Сharged Cations in the Outer Sphere

Radiochemistry - Nitrate complexes of pentavalent neptunium of composition [H3O][C(NH2)3]2[NpO2(NO3)2]3 (I), [N(CH3)4][NpO2(NO3)2(H2O)2] (II), and [HIm][NpO2(Im)5](NO3)2 (III) (Im stands for...     

Crystal structure of a Pu(VII) potassium salt,K<Subscript>3</Subscript>PuO<Subscript>4</Subscript>(OH)<Subscript>2</Subscript>·2H<Subscript>2</Subscript>O

A new Pu(VII) compound, K₃PuO₄(OH)₂·2H₂O, was synthesized, and its structure was studied by single crystal X-ray diffraction. This compound is isostructural to the previously described K₃NpO₄(OH)₂·2H₂O. The structure of the latter compound was redetermined to obtain more precise interatomic distances in the NpO₂(OH) ₂ ^3? anion. Changes in An-O bond lengths in the tetragon-bipyramidal coordination polyhedron of the compounds K₃AnO₄(OH)₂·2H₂O in going from Np(VII) to Pu(VII) were considered.     

Synthesis and crystal structure of new U(VI) and Np(VI) benzoates, K11(AnO2)23(OOCC6H5)57(H2O)18+x

The structure of new double benzoates of hexavalent actinides, K₁₁(AnO₂)₂₃(O₂C₇H₅)₅₇(H₂O)_18+x (An = U, Np), was studied. There are five crystallographically independent actinide atoms in the crystals. The coordination polyhedra of An(1), An(3), An(4), and An(5) are distorted hexagonal bipyramids, and that of An(2) is a distorted pentagonal bipyramid. Ten crystallographically independent benzoate ions have been found in the crystals. All but one anions are bidentate chelating and form with AnO₂²⁺ cations either electrically neutral [AnO₂(O₂C₇H₅)₂(H₂O)₂][An(1)O₂²⁺ cations] or negatively charged [AnO₂(O₂C₇H₅)₃]⁻[An(3)O₂²⁺, An(4)O₂²⁺, An(5)O₂²⁺ cations] complexes. The bidentate bridging benzoate ion links two adjacent An(2)O₂²⁺ cations with the formation of peculiar electrically neutral cyclic fragments [AnO₂(O₂C₇H₅)₂(H₂O)]₆ arranged perpendicular to the c-axis. There are three independent K⁺ cations in the structure. The coordination surrounding of K(1)⁺ (coordination number CN 6) is formed by oxygen atoms of two electrically neutral [AnO₂(O₂C₇H₅)₂(H₂O)₂] fragments and of the complex anion [AnO₂(O₂C₇H₅)₃]⁻. The coordination surrounding of K(2)⁺ (CN 6) consists of oxygen atoms of three complex anions [AnO₂(O₂C₇H₅)₃]⁻. The disordered K(3)⁺ cation is arranged near the sixfold axis between the cyclic fragments [AnO₂(O₂C₇H₅)₂(H₂O)]₆. An important structure-forming factor in the crystals is hydrogen bonding involving coordinated water molecules. In the coordination polyhedra of actinides, the An-O bond lengths regularly decrease in going from U to Np owing to actinide contraction.