DOI: 10.17188/1204468
title: Materials Data on Na2Al2Sb3 by Materials Project

description: Na2Al2Sb3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five Sb+2.67- atoms. There are a spread of Na–Sb bond distances ranging from 3.12–3.66 Å. In the second Na1+ site, Na1+ is bonded to five Sb+2.67- atoms to form distorted NaSb5 trigonal bipyramids that share corners with four equivalent NaSb6 pentagonal pyramids, corners with seven AlSb4 tetrahedra, an edgeedge with one NaSb6 pentagonal pyramid, edges with three AlSb4 tetrahedra, and an edgeedge with one NaSb5 trigonal bipyramid. There are a spread of Na–Sb bond distances ranging from 3.28–3.51 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Sb+2.67- atoms. There are a spread of Na–Sb bond distances ranging from 3.22–3.69 Å. In the fourth Na1+ site, Na1+ is bonded to six Sb+2.67- atoms to form distorted NaSb6 pentagonal pyramids that share corners with eight AlSb4 tetrahedra, corners with four equivalent NaSb5 trigonal bipyramids, an edgeedge with one NaSb6 pentagonal pyramid, edges with four AlSb4 tetrahedra, and an edgeedge with one NaSb5 trigonal bipyramid. There are a spread of Na–Sb bond distances ranging from 3.24–3.40 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Sb+2.67- atoms to form AlSb4 tetrahedra that share a cornercorner with one NaSb6 pentagonal pyramid, corners with five AlSb4 tetrahedra, corners with three equivalent NaSb5 trigonal bipyramids, an edgeedge with one NaSb6 pentagonal pyramid, and an edgeedge with one AlSb4 tetrahedra. There are a spread of Al–Sb bond distances ranging from 2.69–2.80 Å. In the second Al3+ site, Al3+ is bonded to four Sb+2.67- atoms to form AlSb4 tetrahedra that share corners with two equivalent NaSb6 pentagonal pyramids, corners with five AlSb4 tetrahedra, a cornercorner with one NaSb5 trigonal bipyramid, and an edgeedge with one AlSb4 tetrahedra. There are a spread of Al–Sb bond distances ranging from 2.71–2.76 Å. In the third Al3+ site, Al3+ is bonded to four Sb+2.67- atoms to form AlSb4 tetrahedra that share corners with three equivalent NaSb6 pentagonal pyramids, corners with five AlSb4 tetrahedra, corners with two equivalent NaSb5 trigonal bipyramids, an edgeedge with one NaSb6 pentagonal pyramid, an edgeedge with one AlSb4 tetrahedra, and an edgeedge with one NaSb5 trigonal bipyramid. There are a spread of Al–Sb bond distances ranging from 2.69–2.77 Å. In the fourth Al3+ site, Al3+ is bonded to four Sb+2.67- atoms to form AlSb4 tetrahedra that share corners with two equivalent NaSb6 pentagonal pyramids, corners with five AlSb4 tetrahedra, a cornercorner with one NaSb5 trigonal bipyramid, edges with two equivalent NaSb6 pentagonal pyramids, an edgeedge with one AlSb4 tetrahedra, and edges with two equivalent NaSb5 trigonal bipyramids. There are a spread of Al–Sb bond distances ranging from 2.71–2.73 Å. There are six inequivalent Sb+2.67- sites. In the first Sb+2.67- site, Sb+2.67- is bonded to four Na1+ and three Al3+ atoms to form edge-sharing SbNa4Al3 pentagonal bipyramids. In the second Sb+2.67- site, Sb+2.67- is bonded in a 6-coordinate geometry to three Na1+ and three Al3+ atoms. In the third Sb+2.67- site, Sb+2.67- is bonded to four Na1+ and three Al3+ atoms to form edge-sharing SbNa4Al3 pentagonal bipyramids. In the fourth Sb+2.67- site, Sb+2.67- is bonded in a 7-coordinate geometry to four Na1+, two Al3+, and one Sb+2.67- atom. The Sb–Sb bond length is 2.93 Å. In the fifth Sb+2.67- site, Sb+2.67- is bonded in a 6-coordinate geometry to three Na1+ and three Al3+ atoms. In the sixth Sb+2.67- site, Sb+2.67- is bonded in a 7-coordinate geometry to four Na1+, two Al3+, and one Sb+2.67- atom.