Materials Data on NaMnSe2 by Materials Project

Abstract

NaMnSe2 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with six equivalent MnSe4 tetrahedra, edges with six equivalent NaSe6 octahedra, and edges with three equivalent MnSe4 tetrahedra. There are three shorter (2.92 Å) and three longer (3.16 Å) Na–Se bond lengths. Mn3+ is bonded to four Se2- atoms to form MnSe4 tetrahedra that share corners with six equivalent NaSe6 octahedra, corners with six equivalent MnSe4 tetrahedra, and edges with three equivalent NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 19–53°. There are one shorter (2.30 Å) and three longer (2.54 Å) Mn–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three equivalent Na1+ and one Mn3+ atom. In the second Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent Mn3+ atoms to form distorted edge-sharing SeNa3Mn3 octahedra.