Tm2V2O7 crystallizes in the cubic Fd-3m space group. Tm(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1) and six equivalent O(2) atoms. V(1) is bonded to six equivalent O(2) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tm(1) atoms to form OTm4 tetrahedra that share corners with four equivalent O(1)Tm4 tetrahedra, corners with twelve equivalent O(2)Tm2V2 tetrahedra, and edges with six equivalent O(2)Tm2V2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Tm(1) and two equivalent V(1) atoms to form distorted OTm2V2 tetrahedra that share corners with two equivalent O(1)Tm4 tetrahedra, corners with twelve equivalent O(2)Tm2V2 tetrahedra,  an edgeedge with one O(1)Tm4 tetrahedra, and edges with four equivalent O(2)Tm2V2 tetrahedra.
Tm2V2O7 crystallizes in the cubic Fd-3m space group. Tm(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1) and six equivalent O(2) atoms. Both Tm(1)-O(1) bond lengths are 2.15 Å. All Tm(1)-O(2) bond lengths are 2.41 Å. V(1) is bonded to six equivalent O(2) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 50°. All V(1)-O(2) bond lengths are 1.93 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tm(1) atoms to form OTm4 tetrahedra that share corners with four equivalent O(1)Tm4 tetrahedra, corners with twelve equivalent O(2)Tm2V2 tetrahedra, and edges with six equivalent O(2)Tm2V2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Tm(1) and two equivalent V(1) atoms to form distorted OTm2V2 tetrahedra that share corners with two equivalent O(1)Tm4 tetrahedra, corners with twelve equivalent O(2)Tm2V2 tetrahedra,  an edgeedge with one O(1)Tm4 tetrahedra, and edges with four equivalent O(2)Tm2V2 tetrahedra.