Materials Data on K6NbAs3O by Materials Project

Abstract

K6NbAs3O crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a distorted single-bond geometry to one K1+, four equivalent As3-, and one O2- atom. The K–K bond length is 3.60 Å. There are a spread of K–As bond distances ranging from 3.34–3.65 Å. The K–O bond length is 2.71 Å. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to three equivalent K1+ and six equivalent As3- atoms. There are three shorter (3.80 Å) and three longer (3.89 Å) K–As bond lengths. In the third K1+ site, K1+ is bonded to three equivalent As3- and one O2- atom to form KAs3O trigonal pyramids that share corners with four equivalent NbAs3O tetrahedra. All K–As bond lengths are 3.21 Å. The K–O bond length is 2.94 Å. In the fourth K1+ site, K1+ is bonded in a distorted trigonal non-coplanar geometry to three equivalent As3- atoms. All K–As bond lengths are 3.46 Å. Nb5+ is bonded to three equivalent As3- and one O2- atom to form distorted NbAs3O tetrahedra that share corners with four equivalent KAs3O trigonal pyramids. All Nb–As bond lengths are 2.54 Å. The Nb–O bond length is 1.86 Å. As3- is bonded in a 1-coordinate geometry to eight K1+ and one Nb5+ atom. O2- is bonded in a 1-coordinate geometry to four K1+ and one Nb5+ atom.