Materials Data on FeNiPO5 by Materials Project
FeNiPO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with two equivalent NiO6 octahedra, corners with four equivalent PO4 tetrahedra, and faces with two equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 46–62°. There are a spread of Fe–O bond distances ranging from 1.93–2.34 Å. Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four equivalent PO4 tetrahedra, edges with two equivalent NiO6 octahedra, and faces with two equivalent FeO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are four shorter (2.08 Å) and two longer (2.18 Å) Ni–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent FeO6 octahedra and corners with four equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 33–54°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Fe3+ and two equivalent Ni2+ atoms to form distorted corner-sharing OFe2Ni2 trigonal pyramids. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Fe3+, two equivalent Ni2+, and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe3+, one Ni2+, and one P5+ atom.