Materials Data on KLaSiSe4 by Materials Project
KLaSiSe4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.47–3.83 Å. La3+ is bonded to seven Se2- atoms to form distorted LaSe7 pentagonal bipyramids that share corners with two equivalent LaSe7 pentagonal bipyramids, a cornercorner with one SiSe4 tetrahedra, edges with two equivalent LaSe7 pentagonal bipyramids, and edges with three equivalent SiSe4 tetrahedra. There are a spread of La–Se bond distances ranging from 3.04–3.24 Å. Si4+ is bonded to four Se2- atoms to form SiSe4 tetrahedra that share a cornercorner with one LaSe7 pentagonal bipyramid and edges with three equivalent LaSe7 pentagonal bipyramids. There are a spread of Si–Se bond distances ranging from 2.26–2.30 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent K1+, one La3+, and one Si4+ atom. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+, two equivalent La3+, and one Si4+ atom. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+, two equivalent La3+, and one Si4+ atom. In the fourth Se2- site, Se2- is bonded in a distorted see-saw-like geometry to one K1+, two equivalent La3+, and one Si4+ atom.