TY - JOUR
T1 - Uranium Tellurides
T2 - New One- and Two-Dimensional Compounds CsUTe6, CsTiUTes, Cs8Hf5UTe3o.6, and CsCuUTe3
AU - Cody, Jason A.
AU - Ibers, James A.
PY - 1995/6/1
Y1 - 1995/6/1
N2 - The new compounds CsUTe6, CsTiUTe5, Cs8HfsUTe30.6, and CsCuUTe3 have been synthesized through the reaction of the metals with a Cs2Ten flux. CsUTe6 crystallizes in space group D2h16-Pnma of the orthorhombic system with eight formula units in a cell of dimensions a = 30.801(7), b = 8.143(2), and c = 9.174(2) Å and V = 2301(1) Å3 (T = 113 K). CsTiUTe5 crystallizes in space group D2h5-Pmma of the orthorhombic system with two formula units in a cell of dimensions a = 6.130(1), b = 8.240(2), and c = 10.363(2) Å and V = 523.4(2) Å3 (T = 113 K). Cs8Hf5UTe30.6 crystallizes in space group C2H5-P21/c of the monoclinic system with four formula units in a cell of dimensions a = 12.043(3), b = 18.724(4), and c = 30.496(6) Å, β = 97.64(3)°, and V = 6816(2) Å3 (T= 113 K). CsCuUTe3 crystallizes in space group D2h17-Cmcm of the orthorhombic system with four formula units in a cell of dimensions a = 4.327(1), b = 16.661(4), and c = 11.337(3) Å, and V= 817.3(3) Å3 (T = 113 K). The structures of all four compounds were determined by single-crystal X-ray methods. CsUTe6 has a one-dimensional structure that contains pairs of U/Te chains coupled by Te-Te bonds and separated by Cs+ cations. There are many Te-Te distances less than 3.1 Å; if an arbitrary maximum Te-Te single bond distance is taken as 2.98 Å, then the chains may be formulated 1∞[U2(Te3)3(Te2)(Te)2‒], with U in the +IV oxidation state. The U atoms are coordinated to nine Te atoms in a tricapped trigonal-prismatic arrangement. Electrical resistivity measurements give conductivities of 1.6(4) × 10‒2 Ω‒1 cm‒1 (298 K) and 1.5(2) × 10‒3 Ω‒1 cm‒1 (77 K). CsTiUTe5 has a layered structure that contains UTe8 bicapped trigonal prisms sharing a common edge and TiTe6 octahedra sharing faces. Cs+ cations, located in pentagonal prisms of Te atoms, separate the layers. The structure contains an infinite linear Te-Te chain with a separation of 3.065(1) Å. Assignment from the structural results of formal oxidation states is difficult. Magnetic susceptibility data for CsTiUTe5 give a curvilinear x‒1 vs T plot. When fit to a modified Curie-Weiss law, the values C = 8.8(3) × 10‒2 emu K/mol, ⦵ = −1.5(2) K, and x0 = 2.11(8) × 10‒3 emu/mol result. The value of μeff (300 K) is 2.23(1) μB for each CsTiUTe5 unit. The resistivity of CsTiUTe5 at 77 K is beyond the detection limits of our instrument, but it is 1.2(9) × 10‒3 Ω‒1 cm‒1 at 298 K. Cs8Hf5UTe30.6 is a one-dimensional compound with ordered Hf and U atoms and disordered Te atoms in two unique chains that may be formulated 1∞[Hf3Te15 64_] and l∞[Hf2UTe154‒]. Cs+ cations separate the chains. The Hf and Uatoms are coordinated to Te atoms in a distorted trigonal prismatic framework. Since there are many short Te-Te distances the assignment of formal oxidation states is not possible. CsCuUTe3 is a layered compound with no Te-Te bonding. Formal oxidation states are unambiguously Cs1, Cu1, UIV, and TeII‒. As expected, Cs+ cations separate the 2∞[CuUTe3‒] layers, which contain UTe6 octahedra and CuTe4 tetrahedra. This structure differs markedly from the channel structure of CsAg5Te3 formed through an analogous synthesis with Cu replaced by Ag.
AB - The new compounds CsUTe6, CsTiUTe5, Cs8HfsUTe30.6, and CsCuUTe3 have been synthesized through the reaction of the metals with a Cs2Ten flux. CsUTe6 crystallizes in space group D2h16-Pnma of the orthorhombic system with eight formula units in a cell of dimensions a = 30.801(7), b = 8.143(2), and c = 9.174(2) Å and V = 2301(1) Å3 (T = 113 K). CsTiUTe5 crystallizes in space group D2h5-Pmma of the orthorhombic system with two formula units in a cell of dimensions a = 6.130(1), b = 8.240(2), and c = 10.363(2) Å and V = 523.4(2) Å3 (T = 113 K). Cs8Hf5UTe30.6 crystallizes in space group C2H5-P21/c of the monoclinic system with four formula units in a cell of dimensions a = 12.043(3), b = 18.724(4), and c = 30.496(6) Å, β = 97.64(3)°, and V = 6816(2) Å3 (T= 113 K). CsCuUTe3 crystallizes in space group D2h17-Cmcm of the orthorhombic system with four formula units in a cell of dimensions a = 4.327(1), b = 16.661(4), and c = 11.337(3) Å, and V= 817.3(3) Å3 (T = 113 K). The structures of all four compounds were determined by single-crystal X-ray methods. CsUTe6 has a one-dimensional structure that contains pairs of U/Te chains coupled by Te-Te bonds and separated by Cs+ cations. There are many Te-Te distances less than 3.1 Å; if an arbitrary maximum Te-Te single bond distance is taken as 2.98 Å, then the chains may be formulated 1∞[U2(Te3)3(Te2)(Te)2‒], with U in the +IV oxidation state. The U atoms are coordinated to nine Te atoms in a tricapped trigonal-prismatic arrangement. Electrical resistivity measurements give conductivities of 1.6(4) × 10‒2 Ω‒1 cm‒1 (298 K) and 1.5(2) × 10‒3 Ω‒1 cm‒1 (77 K). CsTiUTe5 has a layered structure that contains UTe8 bicapped trigonal prisms sharing a common edge and TiTe6 octahedra sharing faces. Cs+ cations, located in pentagonal prisms of Te atoms, separate the layers. The structure contains an infinite linear Te-Te chain with a separation of 3.065(1) Å. Assignment from the structural results of formal oxidation states is difficult. Magnetic susceptibility data for CsTiUTe5 give a curvilinear x‒1 vs T plot. When fit to a modified Curie-Weiss law, the values C = 8.8(3) × 10‒2 emu K/mol, ⦵ = −1.5(2) K, and x0 = 2.11(8) × 10‒3 emu/mol result. The value of μeff (300 K) is 2.23(1) μB for each CsTiUTe5 unit. The resistivity of CsTiUTe5 at 77 K is beyond the detection limits of our instrument, but it is 1.2(9) × 10‒3 Ω‒1 cm‒1 at 298 K. Cs8Hf5UTe30.6 is a one-dimensional compound with ordered Hf and U atoms and disordered Te atoms in two unique chains that may be formulated 1∞[Hf3Te15 64_] and l∞[Hf2UTe154‒]. Cs+ cations separate the chains. The Hf and Uatoms are coordinated to Te atoms in a distorted trigonal prismatic framework. Since there are many short Te-Te distances the assignment of formal oxidation states is not possible. CsCuUTe3 is a layered compound with no Te-Te bonding. Formal oxidation states are unambiguously Cs1, Cu1, UIV, and TeII‒. As expected, Cs+ cations separate the 2∞[CuUTe3‒] layers, which contain UTe6 octahedra and CuTe4 tetrahedra. This structure differs markedly from the channel structure of CsAg5Te3 formed through an analogous synthesis with Cu replaced by Ag.
UR - http://www.scopus.com/inward/record.url?scp=0001257627&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001257627&partnerID=8YFLogxK
U2 - 10.1021/ic00116a006
DO - 10.1021/ic00116a006
M3 - Article
AN - SCOPUS:0001257627
VL - 34
SP - 3165
EP - 3172
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 12
ER -