Materials Data on NaFe2PbF9 by Materials Project

NaPbFe2F9 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded to eight F1- atoms to form distorted NaF8 hexagonal bipyramids that share corners with two equivalent FeF6 octahedra and edges with four FeF6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Na–F bond distances ranging from 2.27–2.80 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with four FeF6 octahedra and edges with two equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 19–45°. There is two shorter (1.94 Å) and four longer (1.96 Å) Fe–F bond length. In the second Fe3+ site, Fe3+ is bonded to six F1- atoms to form FeF6 octahedra that share corners with two equivalent NaF8 hexagonal bipyramids, corners with two equivalent FeF6 octahedra, and edges with two equivalent NaF8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There is four shorter (1.95 Å) and two longer (1.99 Å) Fe–F bond length. Pb2+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Pb–F bond distances ranging from 2.55–2.98 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to one Na1+ and two Fe3+ atoms. In the second F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Fe3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one Pb2+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Na1+, one Fe3+, and two equivalent Pb2+ atoms. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to one Na1+, one Fe3+, and two equivalent Pb2+ atoms.