Materials Data on KTbGeS4 by Materials Project
KTbGeS4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of K–S bond distances ranging from 3.25–3.68 Å. Tb3+ is bonded to seven S2- atoms to form distorted TbS7 pentagonal bipyramids that share corners with two equivalent TbS7 pentagonal bipyramids, a cornercorner with one GeS4 tetrahedra, edges with two equivalent TbS7 pentagonal bipyramids, and edges with three equivalent GeS4 tetrahedra. There are a spread of Tb–S bond distances ranging from 2.81–2.95 Å. Ge4+ is bonded to four S2- atoms to form GeS4 tetrahedra that share a cornercorner with one TbS7 pentagonal bipyramid and edges with three equivalent TbS7 pentagonal bipyramids. There are a spread of Ge–S bond distances ranging from 2.20–2.24 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent K1+, two equivalent Tb3+, and one Ge4+ atom. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three equivalent K1+, one Tb3+, and one Ge4+ atom. In the third S2- site, S2- is bonded in a distorted see-saw-like geometry to one K1+, two equivalent Tb3+, and one Ge4+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent K1+, two equivalent Tb3+, and one Ge4+ atom.