Tl2GeTe5 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 4-coordinate geometry to four equivalent Te(4) atoms. In the second Tl site, Tl(2) is bonded in a 4-coordinate geometry to four equivalent Te(1) atoms. Ge(1) is bonded to two equivalent Te(2) and two equivalent Te(4) atoms to form edge-sharing GeTe4 tetrahedra. There are four inequivalent Te sites. In the first Te site, Te(1) is bonded in a 6-coordinate geometry to four equivalent Tl(2) and two equivalent Te(3) atoms. In the second Te site, Te(2) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the third Te site, Te(3) is bonded in a rectangular see-saw-like geometry to two equivalent Te(1) and two equivalent Te(4) atoms. In the fourth Te site, Te(4) is bonded to two equivalent Tl(1), one Ge(1), and one Te(3) atom to form a mixture of distorted corner and edge-sharing TeTl2GeTe trigonal pyramids.
Tl2GeTe5 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 4-coordinate geometry to four equivalent Te(4) atoms. All Tl(1)-Te(4) bond lengths are 3.45 Å. In the second Tl site, Tl(2) is bonded in a 4-coordinate geometry to four equivalent Te(1) atoms. All Tl(2)-Te(1) bond lengths are 3.59 Å. Ge(1) is bonded to two equivalent Te(2) and two equivalent Te(4) atoms to form edge-sharing GeTe4 tetrahedra. Both Ge(1)-Te(2) bond lengths are 2.66 Å. Both Ge(1)-Te(4) bond lengths are 2.60 Å. There are four inequivalent Te sites. In the first Te site, Te(1) is bonded in a 6-coordinate geometry to four equivalent Tl(2) and two equivalent Te(3) atoms. Both Te(1)-Te(3) bond lengths are 2.94 Å. In the second Te site, Te(2) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the third Te site, Te(3) is bonded in a rectangular see-saw-like geometry to two equivalent Te(1) and two equivalent Te(4) atoms. Both Te(3)-Te(4) bond lengths are 3.12 Å. In the fourth Te site, Te(4) is bonded to two equivalent Tl(1), one Ge(1), and one Te(3) atom to form a mixture of distorted corner and edge-sharing TeTl2GeTe trigonal pyramids.