DOI: 10.17188/1750520
title: Materials Data on NaHfMg6 by Materials Project

description: NaMg6Hf crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Na is bonded to twelve Mg atoms to form NaMg12 cuboctahedra that share corners with four equivalent NaMg12 cuboctahedra, corners with eight equivalent HfMg12 cuboctahedra, edges with twenty-four MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent NaMg12 cuboctahedra, faces with four equivalent HfMg12 cuboctahedra, and faces with twelve MgNa2Hf2Mg8 cuboctahedra. There are a spread of Na–Mg bond distances ranging from 3.19–3.50 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Hf atoms to form distorted MgNa2Hf2Mg8 cuboctahedra that share corners with twelve equivalent MgNa2Hf2Mg8 cuboctahedra, edges with four equivalent NaMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, edges with sixteen MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent NaMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with fourteen MgNa2Hf2Mg8 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.14–3.27 Å. There are one shorter (3.21 Å) and one longer (3.23 Å) Mg–Hf bond lengths. In the second Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Hf atoms to form distorted MgNa2Hf2Mg8 cuboctahedra that share corners with twelve equivalent MgNa2Hf2Mg8 cuboctahedra, edges with four equivalent NaMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, edges with sixteen MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent NaMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with fourteen MgNa2Hf2Mg8 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.04–3.40 Å. Both Mg–Hf bond lengths are 3.15 Å. In the third Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Hf atoms to form distorted MgNa2Hf2Mg8 cuboctahedra that share corners with twelve MgNa2Hf2Mg8 cuboctahedra, edges with four equivalent NaMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, edges with sixteen MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent NaMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with fourteen MgNa2Hf2Mg8 cuboctahedra. Both Mg–Hf bond lengths are 3.11 Å. In the fourth Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Hf atoms to form MgNa2Hf2Mg8 cuboctahedra that share corners with twelve MgNa2Hf2Mg8 cuboctahedra, edges with four equivalent NaMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, edges with sixteen MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent NaMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with fourteen MgNa2Hf2Mg8 cuboctahedra. Both Mg–Hf bond lengths are 3.13 Å. Hf is bonded to twelve Mg atoms to form HfMg12 cuboctahedra that share corners with four equivalent HfMg12 cuboctahedra, corners with eight equivalent NaMg12 cuboctahedra, edges with twenty-four MgNa2Hf2Mg8 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, faces with four equivalent NaMg12 cuboctahedra, and faces with twelve MgNa2Hf2Mg8 cuboctahedra.