Materials Data on Na6MgCl8 by Materials Project

Na6MgCl8 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Na1+ is bonded to six Cl1- atoms to form NaCl6 octahedra that share corners with six equivalent NaCl6 octahedra, edges with two equivalent MgCl6 octahedra, and edges with eight equivalent NaCl6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are two shorter (2.84 Å) and four longer (2.85 Å) Na–Cl bond lengths. Mg2+ is bonded to six equivalent Cl1- atoms to form MgCl6 octahedra that share edges with twelve equivalent NaCl6 octahedra. All Mg–Cl bond lengths are 2.55 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded to six equivalent Na1+ atoms to form ClNa6 octahedra that share corners with six equivalent ClNa6 octahedra and edges with twelve equivalent ClNa4Mg square pyramids. The corner-sharing octahedral tilt angles are 0°. In the second Cl1- site, Cl1- is bonded to four equivalent Na1+ and one Mg2+ atom to form ClNa4Mg square pyramids that share corners with nine equivalent ClNa4Mg square pyramids, edges with four equivalent ClNa6 octahedra, and edges with four equivalent ClNa4Mg square pyramids.