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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on K7NbAs4 by Materials Project

K7NbAs4 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are five inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to four As3- atoms to form distorted KAs4 tetrahedra that share corners with two equivalent NbAs4 tetrahedra, corners with four equivalent KAs4 tetrahedra, and an edgeedge with one NbAs4 tetrahedra. There are a spread of K–As bond distances ranging from 3.25–3.47 Å. In the second 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 3.44–3.79 Å. In the third K1+ site, K1+ is bonded in a 4-coordinate geometry to one K1+ and four As3- atoms. The K–K bond length is 3.36 Å. There are a spread of K–As bond distances ranging from 3.20–3.56 Å. In the fourth K1+ site, K1+ is bonded in a 5-coordinate geometry to one K1+ and four As3- atoms. There are a spread of K–As bond distances ranging from 3.49–3.87 Å. In the fifth K1+ site, K1+ is bonded in a distorted trigonal non-coplanar geometry to three As3- atoms. There are one shorter (3.26 Å) and two longer (3.36 Å) K–As bond lengths. Nb5+ is bonded to four As3- atoms to form NbAs4 tetrahedra that share corners with four equivalent KAs4 tetrahedra and edges with two equivalent KAs4 tetrahedra. There are a spread of Nb–As bond distances ranging from 2.51–2.56 Å. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 5-coordinate geometry to seven 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 eight K1+ and one Nb5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K9(NbAs3)2 by Materials Project

K9(NbAs3)2 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are nine 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 3.32–3.56 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 3.27–3.73 Å. In the third K1+ site, K1+ is bonded in a 1-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.27–3.76 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 3.41–3.67 Å. In the fifth K1+ site, K1+ is bonded in a 3-coordinate geometry to one K1+ and three As3- atoms. The K–K bond length is 3.46 Å. There are a spread of K–As bond distances ranging from 3.29–3.44 Å. In the sixth 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 3.37–3.74 Å. In the seventh 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 3.23–3.69 Å. In the eighth K1+ site, K1+ is bonded in a 4-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.25–3.76 Å. In the ninth K1+ site, K1+ is bonded in a 4-coordinate geometry to one K1+ and five As3- atoms. There are a spread of K–As bond distances ranging from 3.32–3.74 Å. There are two inequivalent Nb+4.50+ sites. In the first Nb+4.50+ site, Nb+4.50+ is bonded to four As3- atoms to form edge-sharing NbAs4 tetrahedra. There are a spread of Nb–As bond distances ranging from 2.52–2.58 Å. In the second Nb+4.50+ site, Nb+4.50+ is bonded to four As3- atoms to form edge-sharing NbAs4 tetrahedra. There are a spread of Nb–As bond distances ranging from 2.51–2.60 Å. There are six inequivalent As3- sites. In the first As3- site, As3- is bonded in a 2-coordinate geometry to six K1+ and two Nb+4.50+ atoms. In the second As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+ and one Nb+4.50+ atom. In the third As3- site, As3- is bonded in a 1-coordinate geometry to eight K1+ and one Nb+4.50+ atom. In the fourth As3- site, As3- is bonded in a 2-coordinate geometry to six K1+ and two Nb+4.50+ atoms. In the fifth As3- site, As3- is bonded in a 1-coordinate geometry to six K1+ and one Nb+4.50+ atom. In the sixth As3- site, As3- is bonded in a 1-coordinate geometry to eight K1+ and one Nb+4.50+ atom.

36 MATERIALS SCIENCE↗