TbCuTe2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one Cu(1), one Te(3), one Te(4), two equivalent Te(1), and two equivalent Te(2) atoms. In the second Tb site, Tb(2) is bonded to three equivalent Cu(2), three equivalent Te(1), and three equivalent Te(2) atoms to form distorted TbCu3Te6 octahedra that share corners with three equivalent Te(2)Tb3Cu3 pentagonal pyramids, corners with three equivalent Te(4)Tb3Cu3 pentagonal pyramids, and edges with three equivalent Te(2)Tb3Cu3 pentagonal pyramids. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 7-coordinate geometry to three equivalent Tb(1), one Te(3), and three equivalent Te(1) atoms. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one Tb(2), one Te(4), and three equivalent Te(2) atoms. There are four inequivalent Te sites. In the first Te site, Te(1) is bonded in a rectangular see-saw-like geometry to one Tb(2), two equivalent Tb(1), and one Cu(1) atom. In the second Te site, Te(2) is bonded to one Tb(2), two equivalent Tb(1), and three equivalent Cu(2) atoms to form distorted TeTb3Cu3 pentagonal pyramids that share  a cornercorner with one Tb(2)Cu3Te6 octahedra,  a cornercorner with one Te(4)Tb3Cu3 pentagonal pyramid, corners with two equivalent Te(2)Tb3Cu3 pentagonal pyramids,  an edgeedge with one Tb(2)Cu3Te6 octahedra, edges with two equivalent Te(4)Tb3Cu3 pentagonal pyramids, and edges with four equivalent Te(2)Tb3Cu3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 43°. In the third Te site, Te(3) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Tb(1) and one Cu(1) atom. In the fourth Te site, Te(4) is bonded to three equivalent Tb(1) and three equivalent Cu(2) atoms to form distorted TeTb3Cu3 pentagonal pyramids that share corners with three equivalent Tb(2)Cu3Te6 octahedra, corners with three equivalent Te(2)Tb3Cu3 pentagonal pyramids, and edges with six equivalent Te(2)Tb3Cu3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 58°.
TbCuTe2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one Cu(1), one Te(3), one Te(4), two equivalent Te(1), and two equivalent Te(2) atoms. The Tb(1)-Cu(1) bond length is 3.38 Å. The Tb(1)-Te(3) bond length is 3.07 Å. The Tb(1)-Te(4) bond length is 3.15 Å. Both Tb(1)-Te(1) bond lengths are 3.02 Å. Both Tb(1)-Te(2) bond lengths are 3.18 Å. In the second Tb site, Tb(2) is bonded to three equivalent Cu(2), three equivalent Te(1), and three equivalent Te(2) atoms to form distorted TbCu3Te6 octahedra that share corners with three equivalent Te(2)Tb3Cu3 pentagonal pyramids, corners with three equivalent Te(4)Tb3Cu3 pentagonal pyramids, and edges with three equivalent Te(2)Tb3Cu3 pentagonal pyramids. All Tb(2)-Cu(2) bond lengths are 3.46 Å. All Tb(2)-Te(1) bond lengths are 3.09 Å. All Tb(2)-Te(2) bond lengths are 3.14 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 7-coordinate geometry to three equivalent Tb(1), one Te(3), and three equivalent Te(1) atoms. The Cu(1)-Te(3) bond length is 2.69 Å. All Cu(1)-Te(1) bond lengths are 2.65 Å. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one Tb(2), one Te(4), and three equivalent Te(2) atoms. The Cu(2)-Te(4) bond length is 2.61 Å. There are two shorter (2.63 Å) and one longer (2.68 Å) Cu(2)-Te(2) bond length. There are four inequivalent Te sites. In the first Te site, Te(1) is bonded in a rectangular see-saw-like geometry to one Tb(2), two equivalent Tb(1), and one Cu(1) atom. In the second Te site, Te(2) is bonded to one Tb(2), two equivalent Tb(1), and three equivalent Cu(2) atoms to form distorted TeTb3Cu3 pentagonal pyramids that share  a cornercorner with one Tb(2)Cu3Te6 octahedra,  a cornercorner with one Te(4)Tb3Cu3 pentagonal pyramid, corners with two equivalent Te(2)Tb3Cu3 pentagonal pyramids,  an edgeedge with one Tb(2)Cu3Te6 octahedra, edges with two equivalent Te(4)Tb3Cu3 pentagonal pyramids, and edges with four equivalent Te(2)Tb3Cu3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 43°. In the third Te site, Te(3) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Tb(1) and one Cu(1) atom. In the fourth Te site, Te(4) is bonded to three equivalent Tb(1) and three equivalent Cu(2) atoms to form distorted TeTb3Cu3 pentagonal pyramids that share corners with three equivalent Tb(2)Cu3Te6 octahedra, corners with three equivalent Te(2)Tb3Cu3 pentagonal pyramids, and edges with six equivalent Te(2)Tb3Cu3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 58°.