Materials Data on V2Hg2O7 by Materials Project
Hg2V2O7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent V5+ sites. In the first V5+ site, V5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of V–O bond distances ranging from 1.70–2.35 Å. In the second V5+ site, V5+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of V–O bond distances ranging from 1.66–2.06 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to six O2- atoms to form distorted HgO6 octahedra that share corners with two equivalent HgO6 octahedra, edges with two equivalent HgO6 octahedra, and edges with four equivalent HgO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There are a spread of Hg–O bond distances ranging from 2.13–2.69 Å. In the second Hg2+ site, Hg2+ is bonded to seven O2- atoms to form distorted HgO7 pentagonal bipyramids that share edges with four equivalent HgO6 octahedra and edges with two equivalent HgO7 pentagonal bipyramids. There are a spread of Hg–O bond distances ranging from 2.27–2.63 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three V5+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one V5+ and two equivalent Hg2+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two V5+ and one Hg2+ atom. In the fourth O2- site, O2- is bonded to four Hg2+ atoms to form corner-sharing OHg4 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one V5+ and three Hg2+ atoms. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one V5+ and three Hg2+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three V5+ atoms.