Expanding the Remarkable Structural Diversity of Uranyl Tellurites: Hydrothermal Preparation and Structures of K[UO2Te2O5(OH)], Tl3{(UO2)2[Te2O5(OH)](Te2O6)}·2H2O, β-Tl2[UO2(TeO3)2], and Sr3[UO2(TeO3)2](TeO3)2

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Abstract
The reactions of UO2(C2H3O2)2·2H2O with K2TeO3·H2O, Na2TeO3 and TlCl, or Na2TeO3 and Sr(OH)2·8H2O under mild hydrothermal conditions yield K[UO2Te2O5(OH)] (1), Tl3{(UO2)2[Te2O5(OH)](Te2O6)}·2H2O (2) and β-Tl2[UO2(TeO3)2] (3), or Sr3[UO2(TeO3)2](TeO3)2 (4), respectively. The structure of 1 consists of tetragonal bipyramidal U(VI) centers that are bound by terminal oxo groups and tellurite anions. These UO6 units span between one-dimensional chains of corner-sharing, square pyramidal TeO4 polyhedra to create two-dimensional layers. Alternating corner-shared oxygen atoms in the tellurium oxide chains are protonated to create short/long bonding patterns. The one-dimensional chains of corner-sharing TeO4 units found in 1 are also present in 2. However, in 2 there are two distinct chains present, one where alternating corner-shared oxygen atoms are protonated, and one where the chains are unprotonated. The uranyl moieties in 2 are bound by five oxygen atoms from the tellurite chains to create seven-coordinate pentagonal bipyramidal U(VI). The structures of 3 and 4 both contain one-dimensional [UO2(TeO3)2]2- chains constructed from tetragonal bipyramidal U(VI) centers that are bridged by tellurite anions. The chains differ between 3 and 4 in that all of the pyramidal tellurite anions in 3 have the same orientation, whereas the tellurite anions in 4 have opposite orientations on each side of the chain. In 4, there are also additional isolated TeO32- anions present. Crystallographic data: 1, orthorhombic, space group Cmcm, a = 7.9993(5) Å, b = 8.7416(6) Å, c = 11.4413(8) Å, Z = 4; 2, orthorhombic, space group Pbam, a = 10.0623(8) Å, b = 23.024(2) Å, c = 7.9389(6) Å, Z = 4; 3, monoclinic, space group P21/n, a = 5.4766(4) Å, b = 8.2348(6) Å, c = 20.849(3) Å, β = 92.329(1)°, Z = 4; 4, monoclinic, space group C2/c, a = 20.546(1) Å, b = 5.6571(3) Å, c = 13.0979(8) Å, β = 94.416(1)°, Z = 4.