DOI: 10.17188/1677304
title: Materials Data on Ni2As2O7 by Materials Project

description: Ni2As2O7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share a cornercorner with one NiO6 octahedra, corners with four AsO4 tetrahedra, edges with two NiO6 octahedra, and edges with two equivalent AsO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are a spread of Ni–O bond distances ranging from 2.04–2.19 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share corners with six AsO4 tetrahedra and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.07–2.17 Å. In the third Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share corners with five AsO4 tetrahedra, a cornercorner with one AsO5 trigonal bipyramid, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.04–2.21 Å. In the fourth Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one NiO6 octahedra, corners with five AsO4 tetrahedra, edges with two NiO6 octahedra, and an edgeedge with one AsO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 39°. There are a spread of Ni–O bond distances ranging from 1.99–2.16 Å. In the fifth Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share corners with five AsO4 tetrahedra, a cornercorner with one AsO5 trigonal bipyramid, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.04–2.21 Å. In the sixth Ni2+ site, Ni2+ is bonded to six O2- atoms to form distorted NiO6 octahedra that share corners with five AsO4 tetrahedra, a cornercorner with one AsO5 trigonal bipyramid, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 2.05–2.24 Å. There are six inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six NiO6 octahedra, a cornercorner with one AsO4 tetrahedra, and a cornercorner with one AsO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 45–66°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six NiO6 octahedra and a cornercorner with one AsO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 25–57°. There are a spread of As–O bond distances ranging from 1.66–1.80 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six NiO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of As–O bond distances ranging from 1.71–1.74 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six NiO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–68°. There are a spread of As–O bond distances ranging from 1.71–1.77 Å. In the fifth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six NiO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–63°. There is three shorter (1.71 Å) and one longer (1.76 Å) As–O bond length. In the sixth As5+ site, As5+ is bonded to five O2- atoms to form distorted AsO5 trigonal bipyramids that share corners with three NiO6 octahedra, corners with two AsO4 tetrahedra, and edges with three NiO6 octahedra. The corner-sharing octahedra tilt angles range from 29–53°. There are a spread of As–O bond distances ranging from 1.72–2.18 Å. There are twenty-one inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ni2+ and two As5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two As5+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ni2+ and two As5+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two As5+ atoms. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ni2+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Ni2+ and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ni2+ and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ni2+ and one As5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ni2+ and one As5+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ni2+ and one As5+ atom. In the twentieth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ni2+ and one As5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one As5+ atom.