Materials Data on La4SiI5 by Materials Project
La4SiI5 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent La+2.25+ sites. In the first La+2.25+ site, La+2.25+ is bonded to one Si4- and five I1- atoms to form a mixture of edge and corner-sharing LaSiI5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. The La–Si bond length is 2.88 Å. There are a spread of La–I bond distances ranging from 3.24–3.53 Å. In the second La+2.25+ site, La+2.25+ is bonded to two equivalent Si4- and four I1- atoms to form a mixture of edge and corner-sharing LaSi2I4 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. Both La–Si bond lengths are 2.97 Å. There are a spread of La–I bond distances ranging from 3.29–3.46 Å. Si4- is bonded to six La+2.25+ atoms to form edge-sharing SiLa6 octahedra. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted see-saw-like geometry to four La+2.25+ atoms. In the second I1- site, I1- is bonded in a distorted T-shaped geometry to three La+2.25+ atoms. In the third I1- site, I1- is bonded in a square co-planar geometry to four equivalent La+2.25+ atoms.