Sr2Mg1 crystallizes in the hexagonal P-6m2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to six equivalent Sr(1) and six equivalent Sr(2) atoms to form a mixture of corner, face, and edge-sharing SrSr12 cuboctahedra. In the second Sr site, Sr(2) is bonded in a 3-coordinate geometry to three equivalent Sr(1) and three equivalent Mg(1) atoms. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to six equivalent Mg(1) atoms. Mg(1) is bonded in a 6-coordinate geometry to three equivalent Sr(2) and three equivalent Sr(3) atoms.
Sr2Mg1 crystallizes in the hexagonal P-6m2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to six equivalent Sr(1) and six equivalent Sr(2) atoms to form a mixture of corner, face, and edge-sharing SrSr12 cuboctahedra. All Sr(1)-Sr(1) bond lengths are 4.26 Å. All Sr(1)-Sr(2) bond lengths are 4.26 Å. In the second Sr site, Sr(2) is bonded in a 3-coordinate geometry to three equivalent Sr(1) and three equivalent Mg(1) atoms. All Sr(2)-Mg(1) bond lengths are 3.59 Å. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to six equivalent Mg(1) atoms. All Sr(3)-Mg(1) bond lengths are 3.58 Å. Mg(1) is bonded in a 6-coordinate geometry to three equivalent Sr(2) and three equivalent Sr(3) atoms.