Materials Data on K8NbAs5Pb by Materials Project
K8NbPbAs5 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 5-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.47–3.81 Å. In the second 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 3.37–3.44 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 3.29–3.73 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 3.38–3.69 Å. In the fifth K1+ site, K1+ is bonded in a 3-coordinate geometry to one Pb2+ and three As3- atoms. The K–Pb bond length is 3.62 Å. There are a spread of K–As bond distances ranging from 3.34–3.60 Å. In the sixth K1+ site, K1+ is bonded in a 5-coordinate geometry to one Pb2+ and four As3- atoms. The K–Pb bond length is 3.53 Å. There are a spread of K–As bond distances ranging from 3.29–3.78 Å. In the seventh 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 3.40–3.87 Å. In the eighth 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 3.26–3.62 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. Pb2+ is bonded in a 5-coordinate geometry to two K1+ and three As3- atoms. There are a spread of Pb–As bond distances ranging from 2.76–2.90 Å. There are five inequivalent As3- sites. In the first As3- site, As3- is bonded in a 1-coordinate geometry to eight K1+ and one Nb5+ atom. In the second As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+ and one Nb5+ atom. In the third As3- site, As3- is bonded in a 1-coordinate geometry to six K1+, one Nb5+, and one Pb2+ atom. In the fourth As3- site, As3- is bonded in a 1-coordinate geometry to six K1+, one Nb5+, and one Pb2+ atom. In the fifth As3- site, As3- is bonded in a 8-coordinate geometry to seven K1+ and one Pb2+ atom.