A new three-dimensional vanadium selenite, (VO)(2)(SeO3)(3), with isolated and edge-shared VO6 octahedra

Single crystals of (VO)2(SeO3)3 have been prepared from SeO2 and V2O5. The crystal structure has been determined by single-crystal X-ray diffraction. Crystal data: (VO)2(SeO3)3, Mr = 514.75; monoclinic, space group P21a (No. 14); cell parameters a = 9.151(1) Å, b = 6.353(1) Å, c = 14.992(1)Å, β = 93.538(5)°, and Z = 4. The structure consists of VO6 octahedra and SeO3 groups. The vanadium octahedra either are edge-sharing and form [V2O6.66]3.33- groups or are corner-linked through an [SeO3/2]+ cation. The structure may be rationalized in terms of connecting layers of {2[SeO2/2O1/3]4/3+[VO1/1O 4/2O1/3]5/3-}+ cations and {[SeO3/2]+[VO1/1O5/2]2-}- anions. © 1997 American Chemical Society

Synthesis and characterization of Se4Nb2O13: A new ternary Se4+-Nb5+-oxide with monoselenite and diselenite groups

A new noncentrosymmetric ternary selenite, Se4Nb2O13, has been synthesized from SeO2 and Nb2O5. Crystal data: Se4Nb2O13, Mr = 709.64, monoclinic, space group Pa (No. 7), a = 7.555(6) Å, b = 6.637(8) Å, c = 11.377(5) Å, β= 109.23(3)°, V = 538.64(2) Å3 (T = 200 K), Z = 2, R(F) = 6.44%, RW(F) = 7.12%. The compound consists of rows of corner-linked NbO6 octahedra that are also connected through monoselenite, SeO3, and diselenite, Se2O5, groups

Hydro(solvo)thermal synthesis and structure of a three-dimensional zinc fluorophosphate: Zn-2(4,4'-bipy)(PO3F)(2)

A new three-dimensional zinc fluorophosphate is prepared by using hydro(solvo)thermal conditions with ZnO, (HF)x·H3PO4 and 4,4′-bipyridyl; the single-crystal structure is determined

The first fully fluorinated organically templated materials: Synthesis, structures, and physical properties of [H3N(CH2)(3)NH3]U2F10 center dot 2H(2)O, [H3N(CH2)(4)NH3]U2F10 center dot 3H(2)O, [H3N(CH2)(6)NH3]U2F10 center dot 2H(2)O, and [HN(CH2CH2NH3)(3)]U5F24

A series of new layered uranium(IV) fluorides have been prepared under hydrothermal conditions from UO2, HF, and H3PO4 by using H2N(CH2)nNH2 (n = 3, 4, or 6), and N(CH2-CH2NH2)3 as structure-directing agents. [H3N(CH2)3NH3]U2F 10·2H2O (UFO-1), [H3N(CH2)4-NH3]U2F 10·3H2O (UFO-2), [H3N(CH2)6NH3]U2F 10·2H2O (UFO-3), and [HN(CH2CH2NH3)3]-U5F 24 (UFO-4) have been characterized by single-crystal X-ray diffraction, thermogravimetric analysis, BET isotherms, and magnetic susceptibility measurements. UFO-1, 2, 3, and 4 contain negatively charged uranium fluoride (UF) layers constructed from linked UFn polyhedra separated by charge balancing organic cations and occluded water molecules. In UFO-1, 2, and 3, the layers are constructed from equivalent UF9 tricapped trigonal prisms that share three edges and two corners, whereas UFO-4 contains both UF8 bicapped trigonal prisms and UF9 tricapped trigonal prisms. We have demonstrated that the interlamellar organic cations in these materials can be ion-exchanged with a large variety of alkali, alkaline earth, and transition metal cations, thus providing a low-temperature route to new condensed mixed metal uranium fluorides. The magnetic susceptibility data indicate that UFO-1, 2, and 3 exhibit Curie-Wiess behavior between room temperature and 20 K. [Crystal data: UFO-1, monoclinic, space group P21/c (no. 14), a = 10.715(1) Å, b = 7.097(1) Å, c = 8.767(1) Å, β = 93.804(6)°, V = 665.21(1) Å3 (T = 150 K), Z = 2, R(F) = 5.42%, Rw(F) = 6.79%; UFO-2, triclinic, space group P1 (no. 2), a = 12.024(2) Å, b = 7.149(3) Å, c = 8.765(2) Å, α = 90.063(4)°, β = 107.133(5)°, γ = 92.098(3)°, V = 719.49(3) Å3 (T = 150 K), Z = 2, R(F) = 8.05%, Rw(F) = 10.11%; UFO-3, monoclinic, space group P21/c (no. 14), a = 13.800(2) Å, b = 7.056(1) Å, c = 8.720(1) Å, β = 108.338(6)°, V = 805.97(2) Å3 (T = 150 K), Z = 2, R(F) = 3.64%, Rw(F) = 4.65%; UFO-4, triclinic, space group P1 (no. 2), a = 11.534(2) Å, b = 11.532-(4) Å, c = 9.634(2) Å, α = 104.034(4)°, β = 101.112(8)°, γ = 93.922(4)°, V = 1210.9(5) Å3 (T = 150 K), Z = 2, R(F) = 6.12%, Rw(F) = 8.19%.]

New layered uranium phosphate fluorides: syntheses, structures, characterizations, and ion-exchange properties of A(UO2)F(HPO4).xH2O (A = Cs+, Rb+, K+; x = 0-1).

Single crystals of three new layered uranium phosphate fluorides, A(UO2)F(HPO4).xH2O (A = Cs+, Rb+, and K+; x = 0-1) have been synthesized by hydrothermal reactions using UO3, H3PO4, HF, and corresponding alkali metal halides as reagents. Although all three new materials have layered structures, each of them contains different structural motifs within the layer. While Cs(UO2)F(HPO4).0.5H2O and Rb(UO2)F(HPO4) reveal noncentrosymmetric crystal structures, K(UO2)F(HPO4).H2O crystallizes in a centrosymmetric space group. In addition, the ion-exchanged phases for all three materials are highly crystalline. Crystal data: Cs(UO2)F(HPO4).0.5H2O, orthorhombic, space group Pca21 (No. 29), with a = 25.656(5) A, b = 6.0394(12) A, c = 9.2072(18) A, and Z = 4; Rb(UO2)F(HPO4), orthorhombic, space group Cmc21 (No. 36), with a = 17.719(4) A, b = 6.8771(14) A, c = 12.139(2) A, and Z = 8; K(UO2)F(HPO4).H2O, monoclinic, P21/n (No. 14), with a = 6.7885(14) A, b = 8.7024(17) A, c = 12.020(2) A, beta = 94.09(3), and Z = 4

Synthesis and selective topochemical fluorination of the cation and anion-vacancy ordered phases Ba2YCoO5 and Ba3YCo2O7.5.

The synthesis and characterization of two cation-ordered, anion-vacancy ordered phases, Ba2YCoO5 and Ba3YCo2O7.5, is described. Neutron powder diffraction data reveal both phases adopt structures in which octahedral Y(3+) and tetrahedral Co(3+) centers are ordered within a "cubic" perovskite lattice. The unusual ordered pattern adopted by the cations can be attributed to the large concentration of anion vacancies within each phase. Reaction of Ba2YCoO5 with CuF2 under flowing oxygen topochemically inserts fluorine into the host material to form Ba2YCoO5F0.42(1). In contrast Ba2YCoO5 does not intercalate oxygen, even under high oxygen pressure. The selective insertion of fluorine, but not oxygen, into Ba2YCoO5 is discussed and rationalized on the basis of the lattice strain of the resulting oxidized materials. Magnetization and neutron diffraction data reveal Ba3YCo2O7.5 and Ba2YCoO5F0.42 adopt antiferromagnetically ordered states at low-temperature, while in contrast Ba2YCoO5 shows no sign of long-range magnetic order