Materials Data on SrNb2CuO6F by Materials Project

Abstract

SrNb2CuO6F crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Sr2+ is bonded to eight O2- and four equivalent F1- atoms to form SrO8F4 cuboctahedra that share corners with four equivalent SrO8F4 cuboctahedra, faces with four equivalent SrO8F4 cuboctahedra, and faces with four equivalent FSr4Nb2O8 octahedra. There are four shorter (2.71 Å) and four longer (2.73 Å) Sr–O bond lengths. All Sr–F bond lengths are 2.73 Å. Nb5+ is bonded in a 6-coordinate geometry to five O2- and one F1- atom. There are a spread of Nb–O bond distances ranging from 1.83–2.01 Å. The Nb–F bond length is 2.47 Å. Cu1+ is bonded to four equivalent O2- atoms to form distorted corner-sharing CuO4 trigonal pyramids. All Cu–O bond lengths are 2.12 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one Nb5+ and two equivalent Cu1+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Sr2+, two equivalent Nb5+, and two equivalent F1- atoms. Both O–F bond lengths are 2.71 Å. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Sr2+, two equivalent Nb5+, and two equivalent F1- atoms. Both O–F bond lengths are 2.73 Å. F1- is bonded to four equivalent Sr2+, two equivalent Nb5+, and eight O2- atoms to form distorted FSr4Nb2O8 octahedra that share corners with four equivalent FSr4Nb2O8 octahedra, faces with four equivalent SrO8F4 cuboctahedra, and faces with four equivalent FSr4Nb2O8 octahedra. The corner-sharing octahedral tilt angles are 0°.