Tl2Mn2O7 crystallizes in the cubic Fd-3m space group. Mn(1) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra and edges with six equivalent Tl(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. Tl(1) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted TlO8 hexagonal bipyramids that share edges with six equivalent Tl(1)O8 hexagonal bipyramids and edges with six equivalent Mn(1)O6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tl(1) atoms to form corner-sharing OTl4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Mn(1) and two equivalent Tl(1) atoms.
Tl2Mn2O7 crystallizes in the cubic Fd-3m space group. Mn(1) is bonded to six equivalent O(2) atoms to form MnO6 octahedra that share corners with six equivalent Mn(1)O6 octahedra and edges with six equivalent Tl(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. All Mn(1)-O(2) bond lengths are 1.90 Å. Tl(1) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted TlO8 hexagonal bipyramids that share edges with six equivalent Tl(1)O8 hexagonal bipyramids and edges with six equivalent Mn(1)O6 octahedra. Both Tl(1)-O(1) bond lengths are 2.15 Å. All Tl(1)-O(2) bond lengths are 2.47 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tl(1) atoms to form corner-sharing OTl4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Mn(1) and two equivalent Tl(1) atoms.