Materials Data on K3Al4P2O8F9 by Materials Project
K3Al4P2O8F9 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to three O2- and four F1- atoms. There are one shorter (2.88 Å) and two longer (2.99 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.69–3.27 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to four O2- and five F1- atoms. There are two shorter (2.82 Å) and two longer (3.17 Å) K–O bond lengths. There are a spread of K–F bond distances ranging from 2.74–3.11 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to two O2- and four F1- atoms to form AlO2F4 octahedra that share corners with three AlO2F4 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–35°. Both Al–O bond lengths are 1.86 Å. There are a spread of Al–F bond distances ranging from 1.79–1.91 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 four AlO2F4 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–50°. Both Al–O bond lengths are 1.86 Å. There are a spread of Al–F bond distances ranging from 1.83–1.86 Å. In the third Al3+ site, Al3+ is bonded to two equivalent O2- and four F1- atoms to form AlO2F4 octahedra that share corners with four AlO2F4 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–50°. Both Al–O bond lengths are 1.83 Å. There are a spread of Al–F bond distances ranging from 1.84–1.87 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four AlO2F4 octahedra. The corner-sharing octahedra tilt angles range from 40–45°. 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 2-coordinate geometry to two K1+, one Al3+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Al3+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Al3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one P5+ atom. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Al3+ atoms. In the second F1- site, F1- is bonded in a distorted single-bond geometry to three K1+ and one Al3+ atom. In the third F1- site, F1- is bonded in a bent 150 degrees geometry to one K1+ and two Al3+ atoms. In the fourth F1- site, F1- is bonded in a bent 150 degrees geometry to one K1+ and two equivalent Al3+ atoms. In the fifth F1- site, F1- is bonded in a 2-coordinate geometry to one K1+ and two Al3+ atoms. In the sixth F1- site, F1- is bonded in a bent 150 degrees geometry to one K1+ and two Al3+ atoms.