Materials Data on Na2PHO4 by Materials Project

Abstract

Na2HPO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent PO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.36–2.53 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent PO4 tetrahedra and edges with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.40–2.52 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.49 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 38–53°. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.50 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one P5+, and one H1+ atom.