Materials Data on K8NbSnAs5 by Materials Project
K8NbSnAs5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are eight inequivalent K1+ sites. In the first 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 3.33–3.74 Å. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to one K1+ and five As3- atoms. The K–K bond length is 3.57 Å. There are a spread of K–As bond distances ranging from 3.38–3.95 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 3.32–3.69 Å. In the fourth K1+ site, K1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.47–3.82 Å. In the fifth K1+ site, K1+ is bonded to four As3- atoms to form distorted KAs4 tetrahedra that share an edgeedge with one KAs4 tetrahedra and an edgeedge with one NbAs4 tetrahedra. There are a spread of K–As bond distances ranging from 3.37–3.43 Å. In the sixth 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 3.36–3.66 Å. In the seventh K1+ site, K1+ is bonded in a 3-coordinate geometry to three As3- atoms. There are a spread of K–As bond distances ranging from 3.36–3.56 Å. In the eighth K1+ site, K1+ is bonded in a 5-coordinate geometry to one K1+ and five As3- atoms. There are a spread of K–As bond distances ranging from 3.27–3.64 Å. Nb5+ is bonded to four As3- atoms to form NbAs4 tetrahedra that share an edgeedge with one KAs4 tetrahedra. There are a spread of Nb–As bond distances ranging from 2.49–2.58 Å. Sn2+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are a spread of Sn–As bond distances ranging from 2.67–2.79 Å. There are five inequivalent As3- sites. In the first As3- site, As3- is bonded in a 1-coordinate geometry to five K1+, one Nb5+, and one Sn2+ atom. In the second As3- site, As3- is bonded in a 1-coordinate geometry to eight K1+ and one Nb5+ atom. In the third As3- site, As3- is bonded in a 8-coordinate geometry to seven K1+ and one Sn2+ atom. In the fourth As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+, one Nb5+, and one Sn2+ atom. In the fifth As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+ and one Nb5+ atom.