Materials Data on K4Sr2SnAs4 by Materials Project

Abstract

K4Sr2SnAs4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 3-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.36–3.79 Å. In the second K1+ site, K1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.24–3.53 Å. In the third K1+ site, K1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.24–3.48 Å. In the fourth K1+ site, K1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.35–3.56 Å. There are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to five As3- atoms to form distorted SrAs5 square pyramids that share corners with two equivalent SrAs5 square pyramids, a cornercorner with one SnAs4 tetrahedra, and edges with two equivalent SnAs4 tetrahedra. There are a spread of Sr–As bond distances ranging from 3.20–3.64 Å. In the second Sr2+ site, Sr2+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of Sr–As bond distances ranging from 3.21–3.61 Å. Sn4+ is bonded to four As3- atoms to form SnAs4 tetrahedra that share a cornercorner with one SrAs5 square pyramid and edges with two equivalent SrAs5 square pyramids. There are a spread of Sn–As bond distances ranging from 2.65–2.69 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to five K1+, two equivalent Sr2+, and one Sn4+ atom. In the second As3- site, As3- is bonded in a 7-coordinate geometry to four K1+, two Sr2+, and one Sn4+ atom. In the third As3- site, As3- is bonded in a 8-coordinate geometry to four K1+, three Sr2+, and one Sn4+ atom. In the fourth As3- site, As3- is bonded in a 8-coordinate geometry to four K1+, three Sr2+, and one Sn4+ atom.