LiU2TmS3O2 crystallizes in the monoclinic Cm space group. Li(1) is bonded to one S(3) and four equivalent S(2) atoms to form distorted LiS5 square pyramids that share corners with four equivalent Li(1)S5 square pyramids, edges with four equivalent Tm(1)S6 octahedra, and edges with four equivalent Li(1)S5 square pyramids. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 4-coordinate geometry to two equivalent S(2), two equivalent O(1), and two equivalent O(2) atoms. In the second U site, U(2) is bonded in a 4-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. Tm(1) is bonded to one S(1), one S(2), and four equivalent S(3) atoms to form TmS6 octahedra that share corners with four equivalent Tm(1)S6 octahedra, edges with four equivalent Tm(1)S6 octahedra, and edges with four equivalent Li(1)S5 square pyramids. The corner-sharing octahedral tilt angles are 5°. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to four equivalent U(2) and one Tm(1) atom. In the second S site, S(2) is bonded to four equivalent Li(1), two equivalent U(1), and one Tm(1) atom to form distorted SLi4TmU2 pentagonal bipyramids that share corners with four equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with two equivalent O(1)U4 tetrahedra, corners with four equivalent O(2)U4 tetrahedra, edges with two equivalent S(2)Li4TmU2 pentagonal bipyramids, edges with four equivalent S(3)LiTm4 square pyramids,  an edgeedge with one O(1)U4 tetrahedra, and faces with two equivalent S(2)Li4TmU2 pentagonal bipyramids. In the third S site, S(3) is bonded to one Li(1) and four equivalent Tm(1) atoms to form distorted SLiTm4 square pyramids that share corners with four equivalent S(3)LiTm4 square pyramids, edges with four equivalent S(2)Li4TmU2 pentagonal bipyramids, and edges with four equivalent S(3)LiTm4 square pyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with four equivalent O(1)U4 tetrahedra,  an edgeedge with one S(2)Li4TmU2 pentagonal bipyramid, and edges with four equivalent O(2)U4 tetrahedra. In the second O site, O(2) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with four equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with four equivalent O(2)U4 tetrahedra, and edges with four equivalent O(1)U4 tetrahedra.
LiU2TmS3O2 crystallizes in the monoclinic Cm space group. Li(1) is bonded to one S(3) and four equivalent S(2) atoms to form distorted LiS5 square pyramids that share corners with four equivalent Li(1)S5 square pyramids, edges with four equivalent Tm(1)S6 octahedra, and edges with four equivalent Li(1)S5 square pyramids. The Li(1)-S(3) bond length is 2.41 Å. All Li(1)-S(2) bond lengths are 2.75 Å. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 4-coordinate geometry to two equivalent S(2), two equivalent O(1), and two equivalent O(2) atoms. Both U(1)-S(2) bond lengths are 2.92 Å. Both U(1)-O(1) bond lengths are 2.25 Å. Both U(1)-O(2) bond lengths are 2.24 Å. In the second U site, U(2) is bonded in a 4-coordinate geometry to four equivalent S(1), two equivalent O(1), and two equivalent O(2) atoms. All U(2)-S(1) bond lengths are 2.93 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) U(2)-O(1) bond length. Both U(2)-O(2) bond lengths are 2.41 Å. Tm(1) is bonded to one S(1), one S(2), and four equivalent S(3) atoms to form TmS6 octahedra that share corners with four equivalent Tm(1)S6 octahedra, edges with four equivalent Tm(1)S6 octahedra, and edges with four equivalent Li(1)S5 square pyramids. The corner-sharing octahedral tilt angles are 5°. The Tm(1)-S(1) bond length is 2.66 Å. The Tm(1)-S(2) bond length is 2.74 Å. There are two shorter (2.71 Å) and two longer (2.72 Å) Tm(1)-S(3) bond lengths. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to four equivalent U(2) and one Tm(1) atom. In the second S site, S(2) is bonded to four equivalent Li(1), two equivalent U(1), and one Tm(1) atom to form distorted SLi4TmU2 pentagonal bipyramids that share corners with four equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with two equivalent O(1)U4 tetrahedra, corners with four equivalent O(2)U4 tetrahedra, edges with two equivalent S(2)Li4TmU2 pentagonal bipyramids, edges with four equivalent S(3)LiTm4 square pyramids,  an edgeedge with one O(1)U4 tetrahedra, and faces with two equivalent S(2)Li4TmU2 pentagonal bipyramids. In the third S site, S(3) is bonded to one Li(1) and four equivalent Tm(1) atoms to form distorted SLiTm4 square pyramids that share corners with four equivalent S(3)LiTm4 square pyramids, edges with four equivalent S(2)Li4TmU2 pentagonal bipyramids, and edges with four equivalent S(3)LiTm4 square pyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with four equivalent O(1)U4 tetrahedra,  an edgeedge with one S(2)Li4TmU2 pentagonal bipyramid, and edges with four equivalent O(2)U4 tetrahedra. In the second O site, O(2) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with four equivalent S(2)Li4TmU2 pentagonal bipyramids, corners with four equivalent O(2)U4 tetrahedra, and edges with four equivalent O(1)U4 tetrahedra.