SrMg6Si crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms to form a mixture of distorted corner and face-sharing SrMg10Si2 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), and one Si(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), and four equivalent Mg(3) atoms.
SrMg6Si crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms to form a mixture of distorted corner and face-sharing SrMg10Si2 cuboctahedra. Both Sr(1)-Mg(4) bond lengths are 3.39 Å. All Sr(1)-Mg(1) bond lengths are 3.37 Å. There are two shorter (3.26 Å) and two longer (3.49 Å) Sr(1)-Mg(3) bond lengths. Both Sr(1)-Si(1) bond lengths are 3.25 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), and one Si(1) atom. There is one shorter (3.34 Å) and one longer (3.43 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(4) bond lengths are 3.11 Å. The Mg(1)-Si(1) bond length is 2.90 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms. Both Mg(2)-Mg(4) bond lengths are 3.16 Å. All Mg(2)-Mg(3) bond lengths are 3.24 Å. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(4), and two equivalent Si(1) atoms. There is one shorter (3.26 Å) and one longer (3.49 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Si(1) bond lengths are 3.04 Å. In the fourth Mg site, Mg(4) is bonded in a 12-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), and four equivalent Mg(3) atoms.