DOE OSTI2020
ZrCo3(BO4)2 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. Zr4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Zr–O bond distances ranging from 2.04–2.40 Å. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Co–O bond distances ranging from 2.08–2.25 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles are 68°. There are a spread of Co–O bond distances ranging from 2.03–2.27 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing CoO6 octahedra. The corner-sharing octahedral tilt angles are 68°. There are a spread of Co–O bond distances ranging from 2.02–2.29 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.36–1.44 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.36–1.42 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Zr4+ and two Co2+ atoms to form OZr2Co2 tetrahedra that share corners with five OZr2Co2 tetrahedra and edges with three OZr2CoB tetrahedra. In the second O2- site, O2- is bonded to one Zr4+ and three Co2+ atoms to form OZrCo3 tetrahedra that share corners with four OZrCo3 tetrahedra and edges with two equivalent OZr2Co2 tetrahedra. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Co2+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Zr4+, two equivalent Co2+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Co2+ and one B3+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Zr4+, two equivalent Co2+, and one B3+ atom. In the seventh O2- site, O2- is bonded to two equivalent Zr4+, one Co2+, and one B3+ atom to form a mixture of distorted edge and corner-sharing OZr2CoB tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Co2+ and one B3+ atom.