DOI: 10.17188/1698421
title: Materials Data on Mg149I by Materials Project

description: Mg149I is alpha Samarium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are twenty-seven inequivalent Mg sites. In the first Mg site, Mg is bonded in a distorted single-bond geometry to seven Mg and one I atom. There are a spread of Mg–Mg bond distances ranging from 3.11–3.18 Å. The Mg–I bond length is 3.29 Å. In the second Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with sixteen MgMg12 cuboctahedra, an edgeedge with one IMg12 cuboctahedra, edges with thirteen MgMg12 cuboctahedra, and faces with eighteen MgMg12 cuboctahedra. There are six shorter (3.17 Å) and four longer (3.21 Å) Mg–Mg bond lengths. In the third Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.19 Å. In the fourth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with sixteen MgMg12 cuboctahedra, an edgeedge with one IMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with sixteen MgMg12 cuboctahedra. There are four shorter (3.18 Å) and six longer (3.19 Å) Mg–Mg bond lengths. In the fifth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share a cornercorner with one IMg12 cuboctahedra, corners with sixteen MgMg12 cuboctahedra, edges with fourteen MgMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.12–3.20 Å. In the sixth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.19 Å. In the seventh Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are three shorter (3.18 Å) and six longer (3.19 Å) Mg–Mg bond lengths. In the eighth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are three shorter (3.18 Å) and five longer (3.19 Å) Mg–Mg bond lengths. In the ninth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.18 Å. In the tenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with sixteen MgMg12 cuboctahedra, an edgeedge with one IMg12 cuboctahedra, edges with fifteen MgMg12 cuboctahedra, and faces with seventeen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.15–3.20 Å. In the eleventh Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with sixteen MgMg12 cuboctahedra, edges with fifteen MgMg12 cuboctahedra, a faceface with one IMg12 cuboctahedra, and faces with fifteen MgMg12 cuboctahedra. There are three shorter (3.18 Å) and two longer (3.20 Å) Mg–Mg bond lengths. In the twelfth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.18 Å. In the thirteenth Mg site, Mg is bonded in a distorted single-bond geometry to seven Mg and one I atom. All Mg–Mg bond lengths are 3.13 Å. The Mg–I bond length is 3.28 Å. In the fourteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.19 Å. In the fifteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with twelve MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one IMg12 cuboctahedra, and faces with sixteen MgMg12 cuboctahedra. There are three shorter (3.19 Å) and six longer (3.20 Å) Mg–Mg bond lengths. In the sixteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are two shorter (3.18 Å) and seven longer (3.19 Å) Mg–Mg bond lengths. In the seventeenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are two shorter (3.17 Å) and five longer (3.19 Å) Mg–Mg bond lengths. In the eighteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are four shorter (3.18 Å) and three longer (3.19 Å) Mg–Mg bond lengths. In the nineteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are one shorter (3.17 Å) and four longer (3.18 Å) Mg–Mg bond lengths. In the twentieth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share a cornercorner with one IMg12 cuboctahedra, corners with fifteen MgMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with seventeen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.20 Å. In the twenty-first Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are two shorter (3.18 Å) and four longer (3.19 Å) Mg–Mg bond lengths. In the twenty-second Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. There are four shorter (3.18 Å) and two longer (3.19 Å) Mg–Mg bond lengths. In the twenty-third Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. Both Mg–Mg bond lengths are 3.19 Å. In the twenty-fourth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. In the twenty-fifth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.18 Å. In the twenty-sixth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. Both Mg–Mg bond lengths are 3.18 Å. In the twenty-seventh Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, face, and corner-sharing MgMg12 cuboctahedra. Both Mg–Mg bond lengths are 3.18 Å. I is bonded to twelve Mg atoms to form IMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with eight MgMg12 cuboctahedra.