Materials Data on NaCaAlPHO5F2 by Materials Project

Abstract

NaCaAlPHO5F2 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Na1+ is bonded in a 5-coordinate geometry to one O2- and four equivalent F1- atoms. The Na–O bond length is 2.39 Å. There are two shorter (2.35 Å) and two longer (2.51 Å) Na–F bond lengths. Ca2+ is bonded to four O2- and two equivalent F1- atoms to form CaO4F2 octahedra that share corners with two equivalent AlO4F2 octahedra, corners with four equivalent PO4 tetrahedra, and edges with two equivalent CaO4F2 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two shorter (2.35 Å) and two longer (2.40 Å) Ca–O bond lengths. Both Ca–F bond lengths are 2.31 Å. Al3+ is bonded to four O2- and two equivalent F1- atoms to form AlO4F2 octahedra that share corners with two equivalent CaO4F2 octahedra, corners with two equivalent AlO4F2 octahedra, and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–55°. There is two shorter (1.87 Å) and two longer (1.93 Å) Al–O bond length. Both Al–F bond lengths are 1.88 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent AlO4F2 octahedra and corners with four equivalent CaO4F2 octahedra. The corner-sharing octahedra tilt angles range from 44–61°. All P–O bond lengths are 1.55 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Al3+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, two equivalent Al3+, and one H1+ atom. F1- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Ca2+, and one Al3+ atom.