Mg6LaSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), and one Si(1) atom. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent La(1), and two equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), and two equivalent La(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Si(1) atoms. La(1) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Si(1) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(4), four equivalent Mg(2), and two equivalent La(1) atoms.
Mg6LaSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 1-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), and one Si(1) atom. Both Mg(1)-Mg(2) bond lengths are 3.03 Å. Both Mg(1)-Mg(3) bond lengths are 3.06 Å. The Mg(1)-Si(1) bond length is 2.94 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(3), one Mg(4), two equivalent Mg(1), two equivalent Mg(2), two equivalent La(1), and two equivalent Si(1) atoms. The Mg(2)-Mg(3) bond length is 3.20 Å. The Mg(2)-Mg(4) bond length is 3.21 Å. There is one shorter (2.94 Å) and one longer (2.98 Å) Mg(2)-Mg(2) bond length. Both Mg(2)-La(1) bond lengths are 3.32 Å. Both Mg(2)-Si(1) bond lengths are 2.95 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), and two equivalent La(1) atoms. Both Mg(3)-Mg(4) bond lengths are 3.13 Å. Both Mg(3)-La(1) bond lengths are 3.30 Å. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), and two equivalent Si(1) atoms. Both Mg(4)-Si(1) bond lengths are 3.23 Å. La(1) is bonded in a 2-coordinate geometry to two equivalent Mg(3), four equivalent Mg(2), and two equivalent Si(1) atoms. Both La(1)-Si(1) bond lengths are 3.10 Å. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(4), four equivalent Mg(2), and two equivalent La(1) atoms.