One-Dimensional Array of Two- and Three-Center Cation−Cation Bonds in the Structure of Li<sub>4</sub>[(UO<sub>2</sub>)<sub>10</sub>O<sub>10</sub>(Mo<sub>2</sub>O<sub>8</sub>)]

Dark-red crystals of the new compound Li<sub>4</sub>[(UO<sub>2</sub>)<sub>10</sub>O<sub>10</sub>(Mo<sub>2</sub>O<sub>8</sub>)] (<b>1</b>) have been obtained by high-temperature solid-state reactions. The structure of <b>1</b> (monoclinic, <i>P</i>2<sub>1</sub>/<i>c</i>, <i>a</i> = 7.9426(4) Å, <i>b</i> = 19.9895(9) Å, <i>c</i> = 10.0796(5) Å, β = 90.575(2)°, <i>V</i> = 1600.24(13) Å<sup>3</sup>, <i>Z</i> = 4) consists of a framework of U and Mo polyhedra with Li<sup>+</sup> cations in the channels. The framework contains seven-polyhedra-wide uranium oxide tapes interlinked by dimers of edge-sharing [4 + 1]-distorted MoO<sub>5</sub> polyhedra. The U−O tapes are parallel to the <i>a</i> 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.