DOI: 10.17188/1270576
title: Materials Data on Na2Sr2Al2PO4F9 by Materials Project

description: Na2Sr2Al2PO4F9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to two O2- and four F1- atoms. There are one shorter (2.39 Å) and one longer (2.50 Å) Na–O bond lengths. There are a spread of Na–F bond distances ranging from 2.24–2.58 Å. In the second Na1+ site, Na1+ is bonded in a 9-coordinate geometry to one O2- and eight F1- atoms. The Na–O bond length is 2.87 Å. There are a spread of Na–F bond distances ranging from 2.38–2.93 Å. There are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to two O2- and seven F1- atoms. There are one shorter (2.67 Å) and one longer (2.69 Å) Sr–O bond lengths. There are a spread of Sr–F bond distances ranging from 2.49–2.76 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to two O2- and six F1- atoms. There are one shorter (2.63 Å) and one longer (2.72 Å) Sr–O bond lengths. There are a spread of Sr–F bond distances ranging from 2.55–2.63 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to one O2- and five F1- atoms to form AlOF5 octahedra that share a cornercorner with one PO4 tetrahedra. The Al–O bond length is 1.87 Å. There are a spread of Al–F bond distances ranging from 1.82–1.85 Å. In the second Al3+ site, Al3+ is bonded to two equivalent O2- and four F1- atoms to form AlO2F4 octahedra that share corners with two equivalent PO4 tetrahedra. Both Al–O bond lengths are 1.89 Å. There is two shorter (1.83 Å) and two longer (1.85 Å) Al–F bond length. In the third Al3+ site, Al3+ is bonded to two equivalent O2- and four F1- atoms to form AlO2F4 octahedra that share corners with two equivalent PO4 tetrahedra. Both Al–O bond lengths are 1.90 Å. There is two shorter (1.83 Å) and two longer (1.86 Å) Al–F bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three AlOF5 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sr2+, one Al3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+, one Al3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two Sr2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Al3+, and one P5+ atom. There are nine inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to three Na1+, one Sr2+, and one Al3+ atom. In the second F1- site, F1- is bonded in a 1-coordinate geometry to one Na1+, one Sr2+, and one Al3+ atom. In the third F1- site, F1- is bonded in a 1-coordinate geometry to one Na1+, two Sr2+, and one Al3+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Na1+, two Sr2+, and one Al3+ atom. In the fifth F1- site, F1- is bonded in a 1-coordinate geometry to one Na1+, two Sr2+, and one Al3+ atom. In the sixth F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one Sr2+, and one Al3+ atom. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to two Sr2+ and one Al3+ atom. In the eighth F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+, one Sr2+, and one Al3+ atom. In the ninth F1- site, F1- is bonded in a 1-coordinate geometry to two Na1+, one Sr2+, and one Al3+ atom.