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Abstract: Single crystals of the new compounds Li6[(UO2)12(PO4)8(P4O13)] (1), Li5[(UO2)13(AsO4)9(As2O7)] (2), Li[(UO2)4(AsO4)3] (3) and Li3[(UO2)7(AsO4)5O)] (4) have been prepared using high-temperature solid state reactions. The crystal structures have been solved by direct methods: 1—monoclinic, C2/m, a=26.963(3)Å, b=7.063(1)Å, c=19.639(1)Å, β=126.890(4)°, V=2991.2(6)Å3, Z=2, R 1=0.0357 for 3248 unique reflections with |F 0|≥4σF ; 2—triclinic, , a=7.1410(8)Å, b=13.959(1)Å, c=31.925(1)Å, α=82.850(2)°, β=88.691(2)°, γ=79.774(3)°, V=3107.4(4)Å3, Z=2, R 1=0.0722 for 9161 unique reflections with |F 0|≥4σF ; 3—tetragonal, I 41/amd, a=7.160(3)Å, c=33.775(9)Å, V=1732(1)Å3, Z=4, R 1=0.0356 for 318 unique reflections with |F 0|≥4σF ; 4—tetragonal, , a=7.2160(5)Å, c=14.6540(7)Å, V=763.04(8)Å3, Z=1, R 1=0.0423 for 1600 unique reflections with |F 0|≥4σF . Structures of all the phases under consideration are based on complex 3D frameworks consisting of different types of uranium polyhedra (UO6 and UO7) and different types of tetrahedral T O4 anions ( T =P or As): PO4 and P4O13 in 1, AsO4 and As2O7 in 2, and single AsO4 tetrahedra in 3 and 4. In the structures of 1 and 2, UO7 pentagonal bipyramids share edges to form (UO5)∞ chains extended along the b axis in 1 and along the a axis in 2. The chains are linked via single T O4 tetrahedra into tubular units with external diameters of 11Å in 1 and 11.5Å in 2, and internal diameters of 4.1Å in 1 and 4.5Å in 2. The channels accommodate Li+ cations. The tubular units are linked into 3D frameworks by intertubular complexes. Structures of 3 and 4 are based on 3D frameworks composed on layers united by (UO5)∞ infinite chains. Cation–cation interactions are observed in 2, 3, and 4. In 2, the structure contains a trimeric unit with composition [OU(1)O]–U(13)–[OU(2)O]. In the structures of 3 and 4, T-shaped dimers are observed. In all the structures, Li+ cations are located in different types of cages and channels and compensate negative charges of anionic 3D frameworks. [Copyright &y& Elsevier]

Abstract: The three new framework Rb uranyl phosphates and arsenates with anionic parts based on different type of polymeric anions have been prepared by high-temperature solid-state reactions: Rb4[(UO2)6(P2O7)4(H2O)] (1), Rb2[(UO2)3(P2O7)(P4O12)] (2), Rb[(UO2)2(As3O10)] (3). The crystal structures of the synthesized compounds have been solved by direct methods: 1—monoclinic P21/c, a=9.672(1)Å, b=12.951(1)Å, c=32.231(3)Å, β=90.116(4)°, V=4037.3(6)Å3, Z=4, R 1=0.0926 for 6351 unique reflections with ; 2—monoclinic, P21/c, a=6.791(1)Å, b=16.155(3)Å, c=19.856(4)Å, β=97.48(5)°, V=2159.8(7)Å3, Z=4, R 1=0.0286 for 3617 unique reflections with ; 3—orthorhombic, Pbcn, a=10.558(1)Å, b=11.037(1)Å, c=11.464(1)Å, V=1335.9(2)Å3, Z=4, R 1=0.0489 for 1384 unique reflections with . The structures of title are compounds based on 3D negatively charged frameworks with chemical compositions [(UO2)6(P2O7)4(H2O)]4− in 1, [(UO2)3(P2O7)(P4O12)]2− in 2 and [(UO2)2(As3O10)]− in 3. These negative charges are compensated by rubidium cations which are in the channels of 1 and closed cages in structures of 2 and 3. The channels in 1 are directed along the a direction and have minimum dimensions ∼5Å×6Å. This is the first example of porosity generation through solid state synthesis in uranyl compounds. For the first time in uranium chemistry polymeric anionic groups P4O12 and As3O10 were observed in structure of 2 and 3. [Copyright &y& Elsevier]

Abstract: Four new Li uranyl phosphates and arsenates have been prepared by high-temperature solid-state reactions: α-Li[(UO2)(PO4)] (1), α-Li[(UO2)(AsO4)] (2), β-Li[(UO2)(AsO4)] (3) and Li2[(UO2)3(P2O7)2] (4). The structures of the compounds have been solved by direct methods: 1—triclinic, , a=5.0271(1)Å, b=9.8799(2)Å, c=10.8920(2)Å, α=108.282(9)°, β=102.993(8)°, γ=104.13(1)°, V=470.69(2)Å3, Z=4, R 1=0.0415 for 2786 unique reflections with |F 0|⩾4σF ; 2—triclinic, , a=5.129(2)Å, b=10.105(3)Å, c=11.080(3)Å, α=107.70(2)°, β=102.53(3)°, γ=104.74(3)°, V=501.4(3)Å3, Z=4, R 1=0.055 for 1431 unique reflections with |F 0|⩾4σ F; 3—triclinic, , a=5.051(1)Å, b=5.303(1)Å, c=10.101(1)Å, α=90.31(1)°, β=97.49(1)°, γ=105.08(1)°, V=258.80(8)Å3, Z=2, R 1=0.0339 for 2055 unique reflections with |F 0|⩾4σ F; 4—triclinic, , a=5.312(1)Å, b=6.696(1)Å, c=12.542(1)Å, α=94.532(9)°, β=99.059(8)°, γ=110.189(7)°, V=409.17(10)Å3, Z=2, R 1=0.0565 for 1355 unique reflections with |F 0|⩾4σ F. The structures of all four compounds are based upon 3-D frameworks of U and T polyhedra (T=P, As). Phases 1 and 2 are isostructural and consist of U2O12 dimers and UO6 square bipyramids linked by single TO4 tetrahedra. The structure of 3 consists of 3-D framework of corner-sharing UO6 bipyramids and AsO4 tetrahedra. In the structure of 4, the framework is composed of U2O12 dimers, UO6 bipyramids and P2O7 dimers. In all the compounds, Li+ cations reside in framework cavities. The topologies of the 3-D frameworks can be described as derivatives of the PtS (cooperite) network. [Copyright &y& Elsevier]