Materials Data on NaMn4O8 by Materials Project

NaMn4O8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.40 Å) and four longer (2.53 Å) Na–O bond lengths. There are three inequivalent Mn+3.75+ sites. In the first Mn+3.75+ site, Mn+3.75+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There is four shorter (1.95 Å) and two longer (1.97 Å) Mn–O bond length. In the second Mn+3.75+ site, Mn+3.75+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–1.97 Å. In the third Mn+3.75+ site, Mn+3.75+ is bonded to six O2- atoms to form edge-sharing MnO6 octahedra. There are four shorter (1.98 Å) and two longer (2.18 Å) Mn–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to three Mn+3.75+ atoms. In the second O2- site, O2- is bonded to one Na1+ and three Mn+3.75+ atoms to form a mixture of distorted edge and corner-sharing ONaMn3 trigonal pyramids. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and three Mn+3.75+ atoms.