DOI: 10.17188/1674322
title: Materials Data on Mg149Si by Materials Project

description: Mg149Si 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 to eleven Mg and one Si atom to form distorted MgMg11Si cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with nineteen MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.10–3.23 Å. The Mg–Si bond length is 3.14 Å. In the second Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, an edgeedge with one SiMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.20 Å. In the third Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.19 Å. In the fourth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, an edgeedge with one SiMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.21 Å. In the fifth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share a cornercorner with one SiMg12 cuboctahedra, corners with seventeen MgMg11Si cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.20 Å. In the sixth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.20 Å. In the seventh Mg site, Mg is bonded to eleven Mg and one Si atom to form distorted MgMg11Si cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with nineteen MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.12–3.22 Å. The Mg–Si bond length is 3.12 Å. In the eighth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, an edgeedge with one SiMg12 cuboctahedra, edges with seventeen MgMg11Si cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.20 Å. In the ninth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.20 Å. In the tenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are three shorter (3.18 Å) and two longer (3.19 Å) Mg–Mg bond lengths. In the eleventh Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.19 Å. In the twelfth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.17 Å. In the thirteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg11Si cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with nineteen MgMg11Si cuboctahedra. There are one shorter (3.16 Å) and two longer (3.18 Å) Mg–Mg bond lengths. In the fourteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one SiMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are six shorter (3.17 Å) and three longer (3.18 Å) Mg–Mg bond lengths. In the fifteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share a cornercorner with one SiMg12 cuboctahedra, corners with seventeen MgMg11Si cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg11Si cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.20 Å. In the sixteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are three shorter (3.18 Å) and four longer (3.19 Å) Mg–Mg bond lengths. In the seventeenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.18–3.20 Å. In the eighteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.19 Å. In the nineteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg11Si cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are two shorter (3.18 Å) and one longer (3.19 Å) Mg–Mg bond lengths. In the twentieth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. All Mg–Mg bond lengths are 3.19 Å. In the twenty-first Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.19 Å. In the twenty-second Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.18 Å) and two longer (3.20 Å) Mg–Mg bond lengths. In the twenty-third Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.18–3.20 Å. In the twenty-fourth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. There are one shorter (3.18 Å) and two longer (3.19 Å) Mg–Mg bond lengths. In the twenty-fifth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. In the twenty-sixth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.19 Å) and two longer (3.21 Å) Mg–Mg bond lengths. In the twenty-seventh Mg site, Mg is bonded to twelve Mg atoms to form a mixture of edge, corner, and face-sharing MgMg12 cuboctahedra. Si is bonded to twelve Mg atoms to form SiMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg11Si cuboctahedra.