Materials Data on K2NiPCO7 by Materials Project

K2NiCPO7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.60–2.94 Å. Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with four equivalent PO4 tetrahedra. There are a spread of Ni–O bond distances ranging from 1.97–2.26 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.25 Å) and two longer (1.30 Å) C–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 31–39°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent K1+, one Ni3+, and one C4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Ni3+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Ni3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent K1+, one Ni3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Ni3+, and one P5+ atom.