DOE OSTI2020
Zn2P2O7 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to five O2- atoms to form ZnO5 trigonal bipyramids that share corners with five PO4 tetrahedra and edges with two ZnO5 trigonal bipyramids. There are a spread of Zn–O bond distances ranging from 1.97–2.15 Å. In the second Zn2+ site, Zn2+ is bonded to five O2- atoms to form ZnO5 trigonal bipyramids that share corners with five PO4 tetrahedra and edges with two ZnO5 trigonal bipyramids. There are a spread of Zn–O bond distances ranging from 1.93–2.26 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with six ZnO5 trigonal bipyramids. There is three shorter (1.54 Å) and one longer (1.61 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with five ZnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with four ZnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.52–1.65 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zn2+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Zn2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Zn2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent P5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Zn2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zn2+ and one P5+ atom.