Materials Data on SrMg149 by Materials Project
SrMg149 is alpha Samarium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Sr is bonded to twelve Mg atoms to form SrMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. All Sr–Mg bond lengths are 3.34 Å. There are twenty-seven inequivalent Mg sites. In the first Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgSrMg11 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.22 Å. In the second Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, an edgeedge with one SrMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.23 Å. In the third Mg site, Mg is bonded to one Sr and eleven Mg atoms to form distorted MgSrMg11 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one SrMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.10–3.42 Å. In the fourth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share a cornercorner with one SrMg12 cuboctahedra, corners with seventeen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.15–3.22 Å. In the fifth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, an edgeedge with one SrMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.23 Å. In the sixth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.22 Å. In the seventh Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one SrMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.17–3.25 Å. In the eighth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are three shorter (3.21 Å) and six longer (3.22 Å) Mg–Mg bond lengths. In the ninth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.24 Å. In the tenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.18–3.21 Å. In the eleventh Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.17 Å) and three longer (3.20 Å) Mg–Mg bond lengths. In the twelfth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, an edgeedge with one SrMg12 cuboctahedra, edges with seventeen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.18–3.22 Å. In the thirteenth Mg site, Mg is bonded to one Sr and eleven Mg atoms to form distorted MgSrMg11 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one SrMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.12–3.35 Å. In the fourteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.19 Å) and seven longer (3.21 Å) Mg–Mg bond lengths. In the fifteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.20 Å) and five longer (3.21 Å) Mg–Mg bond lengths. In the sixteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are seven shorter (3.20 Å) and two longer (3.21 Å) Mg–Mg bond lengths. In the seventeenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.22 Å. In the eighteenth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.21 Å. In the nineteenth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, a faceface with one SrMg12 cuboctahedra, and faces with nineteen MgMg12 cuboctahedra. There are three shorter (3.19 Å) and six longer (3.23 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 SrMg12 cuboctahedra, corners with seventeen MgMg12 cuboctahedra, edges with eighteen MgMg12 cuboctahedra, and faces with twenty MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.24 Å. In the twenty-first Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.21 Å) and four longer (3.22 Å) Mg–Mg bond lengths. In the twenty-second Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are two shorter (3.20 Å) and two longer (3.22 Å) Mg–Mg bond lengths. In the twenty-third Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.19–3.22 Å. In the twenty-fourth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. In the twenty-fifth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. There are one shorter (3.20 Å) and two longer (3.21 Å) Mg–Mg bond lengths. In the twenty-sixth Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. Both Mg–Mg bond lengths are 3.21 Å. In the twenty-seventh Mg site, Mg is bonded to twelve Mg atoms to form a mixture of corner, edge, and face-sharing MgMg12 cuboctahedra. Both Mg–Mg bond lengths are 3.20 Å.