Mg6GaSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Ga(1), and two equivalent Si(1) atoms to form a mixture of distorted corner, face, and edge-sharing MgMg8Ga2Si2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1), two equivalent Ga(1), and two equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to four equivalent Mg(1) and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a distorted water-like geometry to four equivalent Mg(1) and two equivalent Ga(1) atoms. Ga(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms.
Mg6GaSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Ga(1), and two equivalent Si(1) atoms to form a mixture of distorted corner, face, and edge-sharing MgMg8Ga2Si2 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.23 Å. Both Mg(1)-Mg(2) bond lengths are 3.01 Å. Both Mg(1)-Mg(3) bond lengths are 3.03 Å. Both Mg(1)-Mg(4) bond lengths are 3.03 Å. There is one shorter (3.10 Å) and one longer (3.12 Å) Mg(1)-Ga(1) bond length. There is one shorter (3.10 Å) and one longer (3.12 Å) Mg(1)-Si(1) bond length. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1), two equivalent Ga(1), and two equivalent Si(1) atoms. Both Mg(2)-Ga(1) bond lengths are 3.01 Å. Both Mg(2)-Si(1) bond lengths are 3.01 Å. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to four equivalent Mg(1) and two equivalent Si(1) atoms. Both Mg(3)-Si(1) bond lengths are 2.96 Å. In the fourth Mg site, Mg(4) is bonded in a distorted water-like geometry to four equivalent Mg(1) and two equivalent Ga(1) atoms. Both Mg(4)-Ga(1) bond lengths are 2.96 Å. Ga(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms.