Materials Data on Sr4Nb5O15 by Materials Project
Sr4Nb5O15 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with ten SrO12 cuboctahedra, faces with four SrO12 cuboctahedra, and faces with eight NbO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.81–2.91 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with five SrO12 cuboctahedra, and faces with eight NbO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.79–2.89 Å. There are three inequivalent Nb+4.40+ sites. In the first Nb+4.40+ site, Nb+4.40+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Nb–O bond distances ranging from 2.01–2.06 Å. In the second Nb+4.40+ site, Nb+4.40+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Nb–O bond distances ranging from 1.99–2.07 Å. In the third Nb+4.40+ site, Nb+4.40+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are four shorter (2.03 Å) and two longer (2.04 Å) Nb–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Nb+4.40+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two equivalent Nb+4.40+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Nb+4.40+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Nb+4.40+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Nb+4.40+ atoms. In the sixth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+ and two equivalent Nb+4.40+ atoms.