DOI: 10.17188/1652447
title: Materials Data on NaMg6GaO8 by Materials Project

description: NaMg6GaO8 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent GaO6 octahedra, corners with four equivalent NaO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.16 Å) and two longer (2.35 Å) Na–O bond lengths. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.15 Å) and four longer (2.16 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four equivalent GaO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.09 Å) and four longer (2.16 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, edges with two equivalent NaO6 octahedra, edges with two equivalent GaO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are a spread of Mg–O bond distances ranging from 2.04–2.20 Å. Ga3+ is bonded to six O2- atoms to form GaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent GaO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.89 Å) and four longer (2.16 Å) Ga–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to one Na1+, four equivalent Mg2+, and one Ga3+ atom to form distorted ONaMg4Ga octahedra that share corners with six equivalent ONaMg4Ga octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. In the second O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve ONaMg4Ga octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the third O2- site, O2- is bonded to two equivalent Na1+ and four Mg2+ atoms to form ONa2Mg4 octahedra that share corners with six ONa2Mg4 octahedra and edges with twelve ONaMg4Ga octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to four Mg2+ and two equivalent Ga3+ atoms to form OMg4Ga2 octahedra that share corners with six ONa2Mg4 octahedra and edges with twelve ONaMg4Ga octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded to two equivalent Na1+ and four Mg2+ atoms to form ONa2Mg4 octahedra that share corners with six OMg4Ga2 octahedra and edges with twelve ONaMg4Ga octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.04 Å.