Materials Data on Sr2Mg17 by Materials Project
Mg17Sr2 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 8-coordinate geometry to twenty Mg atoms. There are a spread of Sr–Mg bond distances ranging from 3.63–3.98 Å. In the second Sr site, Sr is bonded in a 12-coordinate geometry to twelve Mg atoms. There are six shorter (3.68 Å) and six longer (3.82 Å) Sr–Mg bond lengths. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 11-coordinate geometry to two Sr and nine Mg atoms. There are a spread of Mg–Mg bond distances ranging from 3.04–3.31 Å. In the second Mg site, Mg is bonded in a 2-coordinate geometry to one Sr and thirteen Mg atoms. There are a spread of Mg–Mg bond distances ranging from 3.05–3.47 Å. In the third Mg site, Mg is bonded to two equivalent Sr and ten Mg atoms to form a mixture of distorted corner and face-sharing MgSr2Mg10 cuboctahedra. All Mg–Mg bond lengths are 3.05 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to two Sr and ten Mg atoms. There are one shorter (3.05 Å) and one longer (3.19 Å) Mg–Mg bond lengths.