USe2 crystallizes in the hexagonal P-62m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 9-coordinate geometry to three equivalent Se(1) and six equivalent Se(2) atoms. In the second U site, U(2) is bonded in a 9-coordinate geometry to three equivalent Se(2) and six equivalent Se(1) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one U(1) and four equivalent U(2) atoms to form distorted SeU5 trigonal bipyramids that share corners with six equivalent Se(2)U4 tetrahedra, corners with ten equivalent Se(1)U5 trigonal bipyramids, edges with six equivalent Se(2)U4 tetrahedra, and edges with six equivalent Se(1)U5 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form SeU4 tetrahedra that share corners with ten equivalent Se(2)U4 tetrahedra, corners with six equivalent Se(1)U5 trigonal bipyramids, edges with two equivalent Se(2)U4 tetrahedra, and edges with six equivalent Se(1)U5 trigonal bipyramids.
USe2 crystallizes in the hexagonal P-62m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 9-coordinate geometry to three equivalent Se(1) and six equivalent Se(2) atoms. All U(1)-Se(1) bond lengths are 3.10 Å. All U(1)-Se(2) bond lengths are 2.89 Å. In the second U site, U(2) is bonded in a 9-coordinate geometry to three equivalent Se(2) and six equivalent Se(1) atoms. All U(2)-Se(2) bond lengths are 2.89 Å. All U(2)-Se(1) bond lengths are 3.14 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to one U(1) and four equivalent U(2) atoms to form distorted SeU5 trigonal bipyramids that share corners with six equivalent Se(2)U4 tetrahedra, corners with ten equivalent Se(1)U5 trigonal bipyramids, edges with six equivalent Se(2)U4 tetrahedra, and edges with six equivalent Se(1)U5 trigonal bipyramids. In the second Se site, Se(2) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form SeU4 tetrahedra that share corners with ten equivalent Se(2)U4 tetrahedra, corners with six equivalent Se(1)U5 trigonal bipyramids, edges with two equivalent Se(2)U4 tetrahedra, and edges with six equivalent Se(1)U5 trigonal bipyramids.