The reaction of UO 3 and TeO 3 with a KCl flux at 800°C for 3 days yields single crystals of K 4 [(UO 2 ) 5 (TeO 3 ) 2 O 5 ]. The structure of the title compound consists of layered, two-dimensional ∞2[(UO2)5(TeO3)2O5]4- sheets arranged in a stair-like topology separated by potassium cations. Contained within these sheets are one-dimensional uranium oxide ribbons consisting of UO 7 pentagonal bipyramids and UO 6 tetragonal bipyramids. The ribbons are in turn linked by corner-sharing with trigonal pyramidal TeO 3 units to form sheets. The lone-pair of electrons from the TeO 3 groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet nonpolar. The potassium cations form contacts with nearby tellurite units and axial uranyl oxygen atoms. Crystallographic data (193K, MoKα, λ=0.71073Å): triclinic, space group P1¯, a=6.8514(5)Å, b=7.1064(5)Å, c=11.3135(8)Å, α=99.642(1)°, β=93.591(1)°, γ=100.506(1)°, V=531.48(7)Å3, Z=1,R(F)=4.19% for 149 parameters and 2583 reflections with I>2σ(I).