Materials Data on Sr3Nb2CoO9 by Materials Project
Sr3Nb2CoO9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.47–3.08 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.45–3.11 Å. In the third Sr2+ site, Sr2+ is bonded in a 2-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.11 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Nb–O bond distances ranging from 1.94–2.00 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra and corners with two equivalent CoO6 octahedra. The corner-sharing octahedra tilt angles range from 3–24°. There are a spread of Nb–O bond distances ranging from 1.97–2.04 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.90 Å) Co–O bond length. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 3–19°. There is two shorter (1.98 Å) and four longer (1.99 Å) Co–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Nb5+, and one Co2+ atom. In the second O2- site, O2- is bonded in a water-like geometry to one Nb5+ and one Co2+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and one Co2+ atom. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four Sr2+, one Nb5+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Sr2+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two equivalent Nb5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+, one Nb5+, and one Co2+ atom.