Materials Data on Na4Mn9O18 by Materials Project
Na4Mn9O18 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.39–2.92 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.40–2.99 Å. In the third 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 2.32–2.47 Å. In the fourth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.72 Å. There are nine inequivalent Mn+3.56+ sites. In the first Mn+3.56+ site, Mn+3.56+ is bonded to five O2- atoms to form MnO5 square pyramids that share corners with six MnO6 octahedra and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 50–62°. There are a spread of Mn–O bond distances ranging from 1.95–2.12 Å. In the second Mn+3.56+ site, Mn+3.56+ is bonded to five O2- atoms to form MnO5 square pyramids that share corners with six MnO6 octahedra and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Mn–O bond distances ranging from 1.94–2.22 Å. In the third Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with two equivalent MnO5 square pyramids, and edges with four MnO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Mn–O bond distances ranging from 1.93–2.22 Å. In the fourth Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with two equivalent MnO5 square pyramids, and edges with four MnO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Mn–O bond distances ranging from 1.94–2.21 Å. In the fifth Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.00 Å. In the sixth Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO5 square pyramids and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.00 Å. In the seventh Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO5 square pyramids and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.93–1.95 Å. In the eighth Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Mn–O bond distances ranging from 1.89–2.01 Å. In the ninth Mn+3.56+ site, Mn+3.56+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Mn–O bond distances ranging from 1.91–2.04 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three Mn+3.56+ atoms. In the second O2- site, O2- is bonded to two equivalent Na1+ and three Mn+3.56+ atoms to form distorted edge-sharing ONa2Mn3 square pyramids. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and three Mn+3.56+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and three Mn+3.56+ atoms. In the fifth O2- site, O2- is bonded to two equivalent Na1+ and three Mn+3.56+ atoms to form distorted edge-sharing ONa2Mn3 trigonal bipyramids. In the sixth O2- site, O2- is bonded to two equivalent Na1+ and three Mn+3.56+ atoms to form distorted edge-sharing ONa2Mn3 trigonal bipyramids. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Na1+ and three Mn+3.56+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+ and three Mn+3.56+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+ and three Mn+3.56+ atoms. In the tenth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Na1+ and three Mn+3.56+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and three Mn+3.56+ atoms. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and three Mn+3.56+ atoms. In the thirteenth O2- site, O2- is bonded to two equivalent Na1+ and three Mn+3.56+ atoms to form a mixture of corner and edge-sharing ONa2Mn3 square pyramids. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Mn+3.56+ atoms. In the fifteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Mn+3.56+ atoms. In the sixteenth O2- site, O2- is bonded to two equivalent Na1+ and three Mn+3.56+ atoms to form a mixture of distorted corner and edge-sharing ONa2Mn3 square pyramids. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to three Na1+ and two equivalent Mn+3.56+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+ and two equivalent Mn+3.56+ atoms.