CsAuUSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Au(1), two equivalent Se(1), and six equivalent Se(2) atoms. U(1) is bonded to four equivalent Au(1), two equivalent Se(1), and four equivalent Se(2) atoms to form a mixture of corner and face-sharing UAu4Se6 octahedra. The corner-sharing octahedral tilt angles are 23°. Au(1) is bonded in a 10-coordinate geometry to two equivalent Cs(1), four equivalent U(1), two equivalent Se(1), and two equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent U(1), and two equivalent Au(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent U(1), and one Au(1) atom.
CsAuUSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Au(1), two equivalent Se(1), and six equivalent Se(2) atoms. Both Cs(1)-Au(1) bond lengths are 4.03 Å. Both Cs(1)-Se(1) bond lengths are 3.70 Å. There are two shorter (3.78 Å) and four longer (3.80 Å) Cs(1)-Se(2) bond lengths. U(1) is bonded to four equivalent Au(1), two equivalent Se(1), and four equivalent Se(2) atoms to form a mixture of corner and face-sharing UAu4Se6 octahedra. The corner-sharing octahedral tilt angles are 23°. All U(1)-Au(1) bond lengths are 3.49 Å. Both U(1)-Se(1) bond lengths are 2.87 Å. All U(1)-Se(2) bond lengths are 2.88 Å. Au(1) is bonded in a 10-coordinate geometry to two equivalent Cs(1), four equivalent U(1), two equivalent Se(1), and two equivalent Se(2) atoms. Both Au(1)-Se(1) bond lengths are 2.70 Å. Both Au(1)-Se(2) bond lengths are 2.57 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent U(1), and two equivalent Au(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent U(1), and one Au(1) atom.