DOI: 10.17188/1284723
title: Materials Data on Na4CaFe4(PO4)6 by Materials Project

description: Na4CaFe4(PO4)6 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.76 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.42–2.71 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.53 Å. Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with two equivalent PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.38 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.73–2.32 Å. In the second Fe3+ site, Fe3+ is bonded in a see-saw-like geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 2.00–2.32 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.50–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share an edgeedge with one CaO6 pentagonal pyramid. There is two shorter (1.54 Å) and two longer (1.58 Å) P–O bond length. In the third P5+ site, P5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.51–1.78 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CaO6 pentagonal pyramids. There is two shorter (1.54 Å) and two longer (1.60 Å) P–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two P5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one Fe3+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Fe3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Ca2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two P5+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Ca2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one Fe3+ and one O2- atom. The O–O bond length is 1.33 Å. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one O2- atom.