One-Dimensional Array of Two- and Three-Center Cation−Cation Bonds in the Structure of Li₄[(UO₂)₁₀O₁₀(Mo₂O₈)]

Dark-red crystals of the new compound Li₄[(UO₂)₁₀O₁₀(Mo₂O₈)] (1) have been obtained by high-temperature solid-state reactions. The structure of 1 (monoclinic, P2₁/c, a = 7.9426(4) Å, b = 19.9895(9) Å, c = 10.0796(5) Å, β = 90.575(2)°, V = 1600.24(13) ų, Z = 4) consists of a framework of U and Mo polyhedra with Li⁺ cations in the channels. The framework contains seven-polyhedra-wide uranium oxide tapes interlinked by dimers of edge-sharing [4 + 1]-distorted MoO₅ polyhedra. The U−O tapes are parallel to the a axis, and their planes are oriented parallel to (021) and (021̄) so that they are cross-linked within the framework. The core of the tapes consists of unprecedented one-dimensional arrays of cation−cation-bonded uranyl ions. The arrays are constructed from eight-membered cycles with uranyl ions linked through two- and three-center cation−cation interactions.