DOI: 10.17188/1759710
title: Materials Data on Sr4Nb2O9 by Materials Project

description: Sr4Nb2O9 is Pb (Zr_0.50 Ti_0.48) O_3-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.39–3.22 Å. In the second Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.32–2.77 Å. In the third Sr2+ site, Sr2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Sr–O bond distances ranging from 2.44–2.60 Å. In the fourth 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 2.31–3.11 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Sr–O bond distances ranging from 2.64–3.22 Å. In the sixth Sr2+ site, Sr2+ is bonded to seven O2- atoms to form distorted SrO7 pentagonal bipyramids that share corners with three equivalent NbO6 octahedra, corners with two equivalent NbO6 pentagonal pyramids, and an edgeedge with one NbO6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 17–33°. There are a spread of Sr–O bond distances ranging from 2.41–2.82 Å. In the seventh Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.35–3.13 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 12-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.62–3.00 Å. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 16–17°. There are a spread of Nb–O bond distances ranging from 1.88–2.23 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 pentagonal pyramids that share corners with two equivalent SrO7 pentagonal bipyramids and an edgeedge with one SrO7 pentagonal bipyramid. There are a spread of Nb–O bond distances ranging from 2.00–2.09 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra and corners with three equivalent SrO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 13–18°. There are a spread of Nb–O bond distances ranging from 1.90–2.21 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 13–18°. There are a spread of Nb–O bond distances ranging from 2.00–2.07 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to five Sr2+ and one Nb5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to five Sr2+ and one Nb5+ atom. In the third O2- site, O2- is bonded to three Sr2+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OSr3Nb trigonal pyramids. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Nb5+ atom. In the fifth O2- site, O2- is bonded to three Sr2+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OSr3Nb tetrahedra. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Nb5+ atom. In the seventh O2- site, O2- is bonded to three Sr2+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OSr3Nb trigonal pyramids. In the eighth O2- site, O2- is bonded to three Sr2+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OSr3Nb trigonal pyramids. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Nb5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and two Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Nb5+ atom. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one Nb5+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Nb5+ atom. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+ and two Nb5+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Nb5+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Nb5+ atoms. In the seventeenth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and two Nb5+ atoms. In the eighteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two Nb5+ atoms.