Materials Data on Na2MnNiO4 by Materials Project

Abstract

Na2MnNiO4 is Caswellsilverite-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with three equivalent MnO6 octahedra, corners with three equivalent NiO6 octahedra, edges with three equivalent MnO6 octahedra, edges with three equivalent NiO6 octahedra, and edges with six equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–13°. There are three shorter (2.33 Å) and three longer (2.47 Å) Na–O bond lengths. Mn2+ is bonded to six equivalent O2- atoms to form MnO6 octahedra that share corners with six equivalent NaO6 octahedra, edges with six equivalent NaO6 octahedra, and edges with six equivalent MnO6 octahedra. The corner-sharing octahedral tilt angles are 13°. All Mn–O bond lengths are 2.06 Å. Ni4+ is bonded to six equivalent O2- atoms to form NiO6 octahedra that share corners with six equivalent NaO6 octahedra, edges with six equivalent NaO6 octahedra, and edges with six equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 10°. All Ni–O bond lengths are 2.05 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Na1+ and three equivalent Ni4+ atoms to form a mixture of edge and corner-sharing ONa3Ni3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O2- site, O2- is bonded to three equivalent Na1+ and three equivalent Mn2+ atoms to form a mixture of edge and corner-sharing ONa3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°.