Pd3Tl2Se2 crystallizes in the trigonal R-3m space group. Pd(1) is bonded to two equivalent Tl(1), two equivalent Tl(2), and two equivalent Se(1) atoms to form distorted PdTl4Se2 octahedra that share corners with two equivalent Tl(1)Pd6Se2 hexagonal bipyramids, corners with twelve equivalent Pd(1)Tl4Se2 octahedra, and faces with four equivalent Pd(1)Tl4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to six equivalent Pd(1) and two equivalent Se(1) atoms to form TlPd6Se2 hexagonal bipyramids that share corners with six equivalent Tl(1)Pd6Se2 hexagonal bipyramids and corners with six equivalent Pd(1)Tl4Se2 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second Tl site, Tl(2) is bonded in a distorted hexagonal planar geometry to six equivalent Pd(1) atoms. Se(1) is bonded in a 4-coordinate geometry to three equivalent Pd(1) and one Tl(1) atom.
Pd3Tl2Se2 crystallizes in the trigonal R-3m space group. Pd(1) is bonded to two equivalent Tl(1), two equivalent Tl(2), and two equivalent Se(1) atoms to form distorted PdTl4Se2 octahedra that share corners with two equivalent Tl(1)Pd6Se2 hexagonal bipyramids, corners with twelve equivalent Pd(1)Tl4Se2 octahedra, and faces with four equivalent Pd(1)Tl4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. Both Pd(1)-Tl(1) bond lengths are 2.93 Å. Both Pd(1)-Tl(2) bond lengths are 3.03 Å. Both Pd(1)-Se(1) bond lengths are 2.46 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded to six equivalent Pd(1) and two equivalent Se(1) atoms to form TlPd6Se2 hexagonal bipyramids that share corners with six equivalent Tl(1)Pd6Se2 hexagonal bipyramids and corners with six equivalent Pd(1)Tl4Se2 octahedra. The corner-sharing octahedral tilt angles are 43°. Both Tl(1)-Se(1) bond lengths are 3.24 Å. In the second Tl site, Tl(2) is bonded in a distorted hexagonal planar geometry to six equivalent Pd(1) atoms. Se(1) is bonded in a 4-coordinate geometry to three equivalent Pd(1) and one Tl(1) atom.