Materials Data on Na5SrNbAs4 by Materials Project

Abstract

Na5SrNbAs4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are five inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five As3- atoms to form distorted NaAs5 square pyramids that share a cornercorner with one NbAs4 tetrahedra, corners with seven NaAs4 trigonal pyramids, edges with two equivalent NaAs5 square pyramids, edges with two equivalent NbAs4 tetrahedra, and edges with four NaAs4 trigonal pyramids. There are a spread of Na–As bond distances ranging from 3.16–3.39 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of Na–As bond distances ranging from 3.12–3.38 Å. In the third Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 trigonal pyramids that share corners with five equivalent NaAs5 square pyramids, corners with two equivalent NbAs4 tetrahedra, corners with eight NaAs4 trigonal pyramids, and an edgeedge with one NbAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.94–3.19 Å. In the fourth Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 trigonal pyramids that share a cornercorner with one NaAs5 square pyramid, corners with two equivalent NbAs4 tetrahedra, corners with eight NaAs4 trigonal pyramids, edges with two equivalent NaAs5 square pyramids, and an edgeedge with one NbAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.95–3.18 Å. In the fifth Na1+ site, Na1+ is bonded to four As3- atoms to form distorted NaAs4 trigonal pyramids that share a cornercorner with one NaAs5 square pyramid, corners with two equivalent NbAs4 tetrahedra, corners with eight NaAs4 trigonal pyramids, edges with two equivalent NaAs5 square pyramids, and an edgeedge with one NbAs4 tetrahedra. There are a spread of Na–As bond distances ranging from 2.98–3.20 Å. Sr2+ is bonded in a 6-coordinate geometry to six As3- atoms. There are a spread of Sr–As bond distances ranging from 3.11–3.65 Å. Nb5+ is bonded to four As3- atoms to form NbAs4 tetrahedra that share a cornercorner with one NaAs5 square pyramid, corners with six NaAs4 trigonal pyramids, edges with two equivalent NaAs5 square pyramids, and edges with three NaAs4 trigonal pyramids. There are a spread of Nb–As bond distances ranging from 2.48–2.53 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to six Na1+, one Sr2+, and one Nb5+ atom. In the second As3- site, As3- is bonded in a 7-coordinate geometry to five Na1+, two equivalent Sr2+, and one Nb5+ atom. In the third As3- site, As3- is bonded in a 8-coordinate geometry to five Na1+, two equivalent Sr2+, and one Nb5+ atom. In the fourth As3- site, As3- is bonded in a 8-coordinate geometry to six Na1+, one Sr2+, and one Nb5+ atom.