Tl2GeTe3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to two equivalent Te(1) and two equivalent Te(2) atoms. In the second Tl site, Tl(2) is bonded in a 3-coordinate geometry to one Te(2) and two equivalent Te(1) atoms. Ge(1) is bonded to one Te(1), one Te(2), one Te(3), and one Te(4) atom to form edge-sharing GeTe4 tetrahedra. There are four inequivalent Te sites. In the first Te site, Te(2) is bonded in a 4-coordinate geometry to one Tl(2), two equivalent Tl(1), and one Ge(1) atom. In the second Te site, Te(3) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the third Te site, Te(4) is bonded in a distorted L-shaped geometry to two equivalent Ge(1) atoms. In the fourth Te site, Te(1) is bonded in a 5-coordinate geometry to two equivalent Tl(1), two equivalent Tl(2), and one Ge(1) atom.
Tl2GeTe3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to two equivalent Te(1) and two equivalent Te(2) atoms. There is one shorter (3.27 Å) and one longer (3.59 Å) Tl(1)-Te(1) bond length. There is one shorter (3.41 Å) and one longer (3.48 Å) Tl(1)-Te(2) bond length. In the second Tl site, Tl(2) is bonded in a 3-coordinate geometry to one Te(2) and two equivalent Te(1) atoms. The Tl(2)-Te(2) bond length is 3.43 Å. There is one shorter (3.53 Å) and one longer (3.54 Å) Tl(2)-Te(1) bond length. Ge(1) is bonded to one Te(1), one Te(2), one Te(3), and one Te(4) atom to form edge-sharing GeTe4 tetrahedra. The Ge(1)-Te(1) bond length is 2.65 Å. The Ge(1)-Te(2) bond length is 2.63 Å. The Ge(1)-Te(3) bond length is 2.70 Å. The Ge(1)-Te(4) bond length is 2.69 Å. There are four inequivalent Te sites. In the first Te site, Te(2) is bonded in a 4-coordinate geometry to one Tl(2), two equivalent Tl(1), and one Ge(1) atom. In the second Te site, Te(3) is bonded in an L-shaped geometry to two equivalent Ge(1) atoms. In the third Te site, Te(4) is bonded in a distorted L-shaped geometry to two equivalent Ge(1) atoms. In the fourth Te site, Te(1) is bonded in a 5-coordinate geometry to two equivalent Tl(1), two equivalent Tl(2), and one Ge(1) atom.