DOE OSTI2020
LiTbSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Li1+ is bonded to six Se2- atoms to form LiSe6 octahedra that share corners with two equivalent TbSe6 octahedra, corners with four equivalent LiSe6 octahedra, edges with four equivalent LiSe6 octahedra, and edges with eight equivalent TbSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are four shorter (2.86 Å) and two longer (2.92 Å) Li–Se bond lengths. Tb3+ is bonded to six Se2- atoms to form TbSe6 octahedra that share corners with two equivalent LiSe6 octahedra, corners with four equivalent TbSe6 octahedra, edges with four equivalent TbSe6 octahedra, and edges with eight equivalent LiSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are four shorter (2.86 Å) and two longer (2.87 Å) Tb–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Li1+ and three equivalent Tb3+ atoms to form a mixture of corner and edge-sharing SeLi3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se2- site, Se2- is bonded to three equivalent Li1+ and three equivalent Tb3+ atoms to form a mixture of corner and edge-sharing SeLi3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the third Se2- site, Se2- is bonded to three equivalent Li1+ and three equivalent Tb3+ atoms to form a mixture of corner and edge-sharing SeLi3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the fourth Se2- site, Se2- is bonded to three equivalent Li1+ and three equivalent Tb3+ atoms to form a mixture of corner and edge-sharing SeLi3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.86 Å) and one longer (2.92 Å) Se–Li bond lengths. There are two shorter (2.86 Å) and one longer (2.87 Å) Se–Tb bond lengths.