Materials Data on Zn3Cr2O7 by Materials Project
Cr2Zn3O7 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Cr4+ is bonded to six O2- atoms to form corner-sharing CrO6 octahedra. The corner-sharing octahedra tilt angles range from 40–44°. There are a spread of Cr–O bond distances ranging from 1.90–2.01 Å. There are two inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are three shorter (2.03 Å) and one longer (2.08 Å) Zn–O bond lengths. In the second Zn2+ site, Zn2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Zn–O bond distances ranging from 1.99–2.03 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Cr4+ and three equivalent Zn2+ atoms to form corner-sharing OZn3Cr tetrahedra. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Cr4+ and one Zn2+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Cr4+ and one Zn2+ atom. In the fourth O2- site, O2- is bonded to two equivalent Cr4+ and two equivalent Zn2+ atoms to form distorted corner-sharing OZn2Cr2 tetrahedra.