Materials Data on Na2CoP2O7 by Materials Project

Abstract

Na2CoP2O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent PO4 tetrahedra, edges with three equivalent NaO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Na–O bond distances ranging from 2.34–2.66 Å. Co2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.97 Å) and two longer (2.03 Å) Co–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent NaO6 octahedra, a cornercorner with one PO4 tetrahedra, and an edgeedge with one NaO6 octahedra. The corner-sharing octahedra tilt angles range from 38–60°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent P5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent Na1+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Na1+, one Co2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Co2+, and one P5+ atom.