Tm5TeSe4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are three inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to three equivalent Te(1) and three equivalent Se(1) atoms to form TmTe3Se3 octahedra that share corners with three equivalent Tm(2)Se6 octahedra, corners with three equivalent Tm(1)Te3Se3 octahedra, edges with three equivalent Tm(2)Se6 octahedra, and edges with nine equivalent Tm(1)Te3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Tm site, Tm(2) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form TmSe6 octahedra that share corners with three equivalent Tm(3)Se6 octahedra, corners with three equivalent Tm(1)Te3Se3 octahedra, edges with three equivalent Tm(3)Se6 octahedra, edges with three equivalent Tm(1)Te3Se3 octahedra, and edges with six equivalent Tm(2)Se6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third Tm site, Tm(3) is bonded to six equivalent Se(2) atoms to form a mixture of edge and corner-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. Te(1) is bonded to six equivalent Tm(1) atoms to form TeTm6 octahedra that share corners with six equivalent Se(1)Tm6 octahedra, edges with six equivalent Te(1)Tm6 octahedra, and edges with six equivalent Se(1)Tm6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Tm(1) and three equivalent Tm(2) atoms to form SeTm6 octahedra that share corners with three equivalent Te(1)Tm6 octahedra, corners with three equivalent Se(2)Tm6 octahedra, edges with three equivalent Te(1)Tm6 octahedra, edges with three equivalent Se(2)Tm6 octahedra, and edges with six equivalent Se(1)Tm6 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. In the second Se site, Se(2) is bonded to three equivalent Tm(2) and three equivalent Tm(3) atoms to form a mixture of edge and corner-sharing SeTm6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
Tm5TeSe4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are three inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to three equivalent Te(1) and three equivalent Se(1) atoms to form TmTe3Se3 octahedra that share corners with three equivalent Tm(2)Se6 octahedra, corners with three equivalent Tm(1)Te3Se3 octahedra, edges with three equivalent Tm(2)Se6 octahedra, and edges with nine equivalent Tm(1)Te3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. All Tm(1)-Te(1) bond lengths are 3.06 Å. All Tm(1)-Se(1) bond lengths are 2.79 Å. In the second Tm site, Tm(2) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form TmSe6 octahedra that share corners with three equivalent Tm(3)Se6 octahedra, corners with three equivalent Tm(1)Te3Se3 octahedra, edges with three equivalent Tm(3)Se6 octahedra, edges with three equivalent Tm(1)Te3Se3 octahedra, and edges with six equivalent Tm(2)Se6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Tm(2)-Se(1) bond lengths are 2.81 Å. All Tm(2)-Se(2) bond lengths are 2.86 Å. In the third Tm site, Tm(3) is bonded to six equivalent Se(2) atoms to form a mixture of edge and corner-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Tm(3)-Se(2) bond lengths are 2.84 Å. Te(1) is bonded to six equivalent Tm(1) atoms to form TeTm6 octahedra that share corners with six equivalent Se(1)Tm6 octahedra, edges with six equivalent Te(1)Tm6 octahedra, and edges with six equivalent Se(1)Tm6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to three equivalent Tm(1) and three equivalent Tm(2) atoms to form SeTm6 octahedra that share corners with three equivalent Te(1)Tm6 octahedra, corners with three equivalent Se(2)Tm6 octahedra, edges with three equivalent Te(1)Tm6 octahedra, edges with three equivalent Se(2)Tm6 octahedra, and edges with six equivalent Se(1)Tm6 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. In the second Se site, Se(2) is bonded to three equivalent Tm(2) and three equivalent Tm(3) atoms to form a mixture of edge and corner-sharing SeTm6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.