RbUAgSe3 crystallizes in the orthorhombic Cmcm space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent Se(2) and six equivalent Se(1) atoms. U(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form USe6 octahedra that share corners with two equivalent U(1)Se6 octahedra, edges with two equivalent U(1)Se6 octahedra, and edges with four equivalent Ag(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. Ag(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra and edges with four equivalent U(1)Se6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Rb(1), two equivalent U(1), and one Ag(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Rb(1), two equivalent U(1), and two equivalent Ag(1) atoms.
RbUAgSe3 crystallizes in the orthorhombic Cmcm space group. Rb(1) is bonded in a 8-coordinate geometry to two equivalent Se(2) and six equivalent Se(1) atoms. Both Rb(1)-Se(2) bond lengths are 3.54 Å. There are two shorter (3.70 Å) and four longer (3.74 Å) Rb(1)-Se(1) bond lengths. U(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form USe6 octahedra that share corners with two equivalent U(1)Se6 octahedra, edges with two equivalent U(1)Se6 octahedra, and edges with four equivalent Ag(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. Both U(1)-Se(2) bond lengths are 2.90 Å. All U(1)-Se(1) bond lengths are 2.88 Å. Ag(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra and edges with four equivalent U(1)Se6 octahedra. Both Ag(1)-Se(1) bond lengths are 2.61 Å. Both Ag(1)-Se(2) bond lengths are 2.68 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Rb(1), two equivalent U(1), and one Ag(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Rb(1), two equivalent U(1), and two equivalent Ag(1) atoms.