Materials Data on Rb5Nb3OF18 by Materials Project
Rb5Nb3OF18 crystallizes in the tetragonal I4cm space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded to twelve F1- atoms to form RbF12 cuboctahedra that share faces with two equivalent RbF12 cuboctahedra and faces with four equivalent NbF7 pentagonal bipyramids. There are a spread of Rb–F bond distances ranging from 2.99–3.26 Å. In the second Rb1+ site, Rb1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Rb–F bond distances ranging from 2.81–3.28 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to seven F1- atoms to form distorted NbF7 pentagonal bipyramids that share faces with two equivalent RbF12 cuboctahedra. There are a spread of Nb–F bond distances ranging from 1.98–2.02 Å. In the second Nb5+ site, Nb5+ is bonded to two equivalent O2- and four equivalent F1- atoms to form corner-sharing NbO2F4 octahedra. The corner-sharing octahedral tilt angles are 0°. There is one shorter (1.81 Å) and one longer (2.18 Å) Nb–O bond length. All Nb–F bond lengths are 1.97 Å. O2- is bonded in a distorted linear geometry to two equivalent Nb5+ atoms. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to three Rb1+ and one Nb5+ atom. In the second F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent Rb1+ and one Nb5+ atom. In the third F1- site, F1- is bonded in a 1-coordinate geometry to three Rb1+ and one Nb5+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to three Rb1+ and one Nb5+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent Rb1+ and one Nb5+ atom. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent Rb1+ and one Nb5+ atom.