Materials Data on Na2Mn3O7 by Materials Project

Abstract

Na2Mn3O7 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–2.38 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.77 Å. There are three inequivalent Mn4+ sites. In the first Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.87–2.04 Å. In the second Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.89–2.03 Å. In the third Mn4+ site, Mn4+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.87–2.03 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to two Na1+ and two Mn4+ atoms to form a mixture of distorted edge and corner-sharing ONa2Mn2 tetrahedra. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three Mn4+ atoms. In the third O2- site, O2- is bonded to one Na1+ and three Mn4+ atoms to form distorted ONaMn3 trigonal pyramids that share corners with six ONaMn3 trigonal pyramids, edges with two equivalent ONa2Mn2 tetrahedra, and an edgeedge with one ONaMn3 trigonal pyramid. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two Mn4+ atoms. In the fifth O2- site, O2- is bonded to one Na1+ and three Mn4+ atoms to form distorted ONaMn3 trigonal pyramids that share corners with two equivalent ONa2Mn2 tetrahedra, corners with three equivalent ONaMn3 trigonal pyramids, and edges with three ONaMn3 trigonal pyramids. In the sixth O2- site, O2- is bonded to two Na1+ and two Mn4+ atoms to form distorted ONa2Mn2 trigonal pyramids that share corners with three equivalent ONa2Mn2 tetrahedra, corners with three equivalent ONaMn3 trigonal pyramids, and edges with two equivalent ONaMn3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Na1+ and three Mn4+ atoms.