Mg2Sb crystallizes in the monoclinic Cm space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Sb(2) and two equivalent Sb(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Sb(1) and three equivalent Sb(2) atoms. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 7-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(4) atoms. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and three equivalent Mg(3) atoms.
Mg2Sb crystallizes in the monoclinic Cm space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 3-coordinate geometry to one Sb(2) and two equivalent Sb(1) atoms. The Mg(1)-Sb(2) bond length is 3.04 Å. Both Mg(1)-Sb(1) bond lengths are 3.15 Å. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. Both Mg(2)-Sb(1) bond lengths are 3.17 Å. Both Mg(2)-Sb(2) bond lengths are 3.06 Å. In the third Mg site, Mg(3) is bonded in a 4-coordinate geometry to one Sb(1) and three equivalent Sb(2) atoms. The Mg(3)-Sb(1) bond length is 3.05 Å. There is one shorter (3.18 Å) and two longer (3.32 Å) Mg(3)-Sb(2) bond lengths. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to two equivalent Sb(1) and two equivalent Sb(2) atoms. Both Mg(4)-Sb(1) bond lengths are 3.05 Å. Both Mg(4)-Sb(2) bond lengths are 3.04 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 7-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(4) atoms. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(2), two equivalent Mg(4), and three equivalent Mg(3) atoms.