Materials Data on Na5Ca4P4O16F by Materials Project
Na5Ca4(PO4)4F crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.91 Å. In the second Na1+ site, Na1+ is bonded in a distorted q6 geometry to eight O2- and two equivalent F1- atoms. There are four shorter (2.62 Å) and four longer (2.92 Å) Na–O bond lengths. Both Na–F bond lengths are 2.74 Å. Ca2+ is bonded in a 8-coordinate geometry to seven O2- and one F1- atom. There are a spread of Ca–O bond distances ranging from 2.35–2.70 Å. The Ca–F bond length is 2.48 Å. P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.55–1.57 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Na1+, one Ca2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Ca2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two equivalent Ca2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Ca2+, and one P5+ atom. F1- is bonded to two equivalent Na1+ and four equivalent Ca2+ atoms to form distorted corner-sharing FNa2Ca4 octahedra. The corner-sharing octahedral tilt angles are 0°.