Materials Data on Sr4NbCoO8 by Materials Project

Abstract

Sr4NbCoO8 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.42–2.82 Å. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.82 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent CoO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.98 Å) and two longer (2.06 Å) Nb–O bond lengths. Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent NbO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.98 Å) and two longer (2.09 Å) Co–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to five Sr2+ and one Co3+ atom to form distorted OSr5Co octahedra that share corners with seventeen OSr4NbCo octahedra, edges with eight OSr5Co octahedra, and faces with four equivalent OSr4NbCo octahedra. The corner-sharing octahedra tilt angles range from 0–56°. In the second O2- site, O2- is bonded to five Sr2+ and one Nb5+ atom to form distorted OSr5Nb octahedra that share corners with seventeen OSr4NbCo octahedra, edges with eight OSr5Co octahedra, and faces with four equivalent OSr4NbCo octahedra. The corner-sharing octahedra tilt angles range from 0–57°. In the third O2- site, O2- is bonded to four Sr2+, one Nb5+, and one Co3+ atom to form a mixture of distorted edge, corner, and face-sharing OSr4NbCo octahedra. The corner-sharing octahedra tilt angles range from 0–57°.