Crystals of four sodium uranyl molybdates, Na3Tl3[(UO2)(MoO4)(4)] (1), Na13-xTl3+x[(UO2)(MoO4)(3)](4)(H2O)(6+x) (x = 0.1) (2), Na3Tl5[(UO2)(MoO4)(3)](2)(H2O)(3) (3) and Na-2[(UO2)(MoO4)(2)](H2O)(4) (4), have been synthesized by hydrothermal methods. The structure of each was solved and refined on the basis of F-2 for all unique data collected using MoKalpha X-radiation and a CCD-based detector. The structure of 1 [orthorhombic, Pbcn, a 20.5823(14), b 7.4391(5), c 26.2514(17) Angstrom, V4019.5(5) Angstrom(3), Z = 8] was refined to an R1 of 0.060. It is based upon a finite cluster with composition [(UO2)(2)(MoO4)(8)](12-) that contains two UrO(5) pentagonal bipyramids and eight MoO4 tetrahedra. The clusters are linked into a framework through distorted Na(1)O-6 and Na(2)O-6 octahedra. The Tl atoms and partially occupied Na(3) and Na(4) sites are located within cavities in the framework. The structure of 2 [monoclinic, P2/c, a 19.7942(11), b 7.1913(4), c 22.8835(13) Angstrom, beta 97.828(1)degrees, V 3227.0(3) Angstrom(3), Z = 2] was refined to an R1 of 0.050. It contains chains of composition [(UO2)(MoO4)(3)](4-) that are parallel to the a axis. The chains are linked into a three-dimensional framework by Naphi(5) and Naphi(6) Polyhedra (phi: O2-, H2O) that share edges. The Tl atoms are located in cavities within the framework. The structure of 3 [orthorhombic, P2(1)2(1)2(1), a 10.7662(6), b 11.9621(6), c 12.8995(7) Angstrom, V 1661.3(2) Angstrom(3), Z = 2] was refined to an R1 of 0.063. It is based on chains of composition [(UO2)(MoO4)(3)](4-) parallel to the c axis that are linked into a framework by Na(1)phi(6) octahedra. The Tl atoms and partially occupied Na(2) sites are located in cavities within the framework. The structure of 4 [monoclinic, P2(1)/n, a 8.9023(5), b 11.5149(6), c 13.8151(7) Angstrom, beta 107.743(1)degrees, V 1348.8(1) Angstrom(3) Z = 4] was refined to an R1 of 0.035. It contains sheets of composition [(UO2)(MoO4)(2)](2-) that are parallel to the ((1) over bar 01) plane. Naphi(6) octahedra share edges with each other, giving chains parallel to the b axis that link adjacent [(UO2)(MoO4)(2)](2-) sheets into a framework. The four structures are compared to those of related uranyl molybdates.
