DOI: 10.17188/1298839
title: Materials Data on Na2NiPCO7 by Materials Project

description: Na2NiCPO7 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are four 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 2.33–2.87 Å. In the second 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 2.34–2.89 Å. In the third Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 pentagonal bipyramids that share a cornercorner with one NiO6 octahedra, corners with two PO4 tetrahedra, an edgeedge with one NiO6 octahedra, an edgeedge with one PO4 tetrahedra, and a faceface with one NiO6 octahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Na–O bond distances ranging from 2.30–2.71 Å. In the fourth 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 2.41–2.79 Å. There are two inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid and corners with four PO4 tetrahedra. There are a spread of Ni–O bond distances ranging from 1.96–2.17 Å. In the second Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with four PO4 tetrahedra, an edgeedge with one NaO7 pentagonal bipyramid, and a faceface with one NaO7 pentagonal bipyramid. There are a spread of Ni–O bond distances ranging from 2.00–2.11 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.26–1.31 Å. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.26 Å) and two longer (1.31 Å) C–O bond length. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four NiO6 octahedra and a cornercorner with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 37–49°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four NiO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 38–47°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Ni3+, and one C4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Ni3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Ni3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one Ni3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ni3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ni3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ni3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni3+, and one C4+ atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Ni3+, and one C4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one C4+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Ni3+, and one C4+ atom.