MgSn2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(1), two equivalent Sn(4), and four equivalent Sn(3) atoms to form distorted MgMg4Sn8 cuboctahedra that share corners with four equivalent Sn(3)Mg6 cuboctahedra, corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(2)Mg4Sn8 cuboctahedra, edges with three equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with four equivalent Sn(3)Mg6 cuboctahedra, faces with two equivalent Mg(2)Mg4Sn8 cuboctahedra, faces with two equivalent Sn(4)Mg4Sn8 cuboctahedra, and faces with four equivalent Mg(1)Mg4Sn8 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(3), two equivalent Sn(4), and four equivalent Sn(2) atoms to form distorted MgMg4Sn8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with three equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with six equivalent Sn(3)Mg6 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn8 cuboctahedra, faces with two equivalent Sn(4)Mg4Sn8 cuboctahedra, and faces with four equivalent Mg(2)Mg4Sn8 cuboctahedra. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted water-like geometry to two equivalent Mg(1) and four equivalent Sn(4) atoms. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to four equivalent Mg(2) and two equivalent Sn(4) atoms. In the third Sn site, Sn(3) is bonded to two equivalent Mg(2) and four equivalent Mg(1) atoms to form distorted SnMg6 cuboctahedra that share corners with four equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with four equivalent Sn(3)Mg6 cuboctahedra, corners with eight equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with two equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with two equivalent Sn(3)Mg6 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with six equivalent Mg(2)Mg4Sn8 cuboctahedra, and faces with two equivalent Sn(3)Mg6 cuboctahedra. In the fourth Sn site, Sn(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(2), two equivalent Sn(4), and four equivalent Sn(1) atoms to form distorted SnMg4Sn8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, corners with eight equivalent Sn(3)Mg6 cuboctahedra, edges with two equivalent Sn(3)Mg6 cuboctahedra, edges with three equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(2)Mg4Sn8 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn8 cuboctahedra, faces with two equivalent Mg(2)Mg4Sn8 cuboctahedra, and faces with four equivalent Sn(4)Mg4Sn8 cuboctahedra.
MgSn2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(1), two equivalent Sn(4), and four equivalent Sn(3) atoms to form distorted MgMg4Sn8 cuboctahedra that share corners with four equivalent Sn(3)Mg6 cuboctahedra, corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(2)Mg4Sn8 cuboctahedra, edges with three equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with four equivalent Sn(3)Mg6 cuboctahedra, faces with two equivalent Mg(2)Mg4Sn8 cuboctahedra, faces with two equivalent Sn(4)Mg4Sn8 cuboctahedra, and faces with four equivalent Mg(1)Mg4Sn8 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.34 Å. Both Mg(1)-Mg(2) bond lengths are 3.39 Å. Both Mg(1)-Sn(1) bond lengths are 3.25 Å. Both Mg(1)-Sn(4) bond lengths are 3.40 Å. All Mg(1)-Sn(3) bond lengths are 3.25 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(3), two equivalent Sn(4), and four equivalent Sn(2) atoms to form distorted MgMg4Sn8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with three equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with six equivalent Sn(3)Mg6 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn8 cuboctahedra, faces with two equivalent Sn(4)Mg4Sn8 cuboctahedra, and faces with four equivalent Mg(2)Mg4Sn8 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.34 Å. Both Mg(2)-Sn(3) bond lengths are 3.26 Å. Both Mg(2)-Sn(4) bond lengths are 3.41 Å. All Mg(2)-Sn(2) bond lengths are 3.23 Å. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted water-like geometry to two equivalent Mg(1) and four equivalent Sn(4) atoms. All Sn(1)-Sn(4) bond lengths are 3.26 Å. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to four equivalent Mg(2) and two equivalent Sn(4) atoms. Both Sn(2)-Sn(4) bond lengths are 3.31 Å. In the third Sn site, Sn(3) is bonded to two equivalent Mg(2) and four equivalent Mg(1) atoms to form distorted SnMg6 cuboctahedra that share corners with four equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with four equivalent Sn(3)Mg6 cuboctahedra, corners with eight equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with two equivalent Sn(4)Mg4Sn8 cuboctahedra, edges with two equivalent Sn(3)Mg6 cuboctahedra, edges with four equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with six equivalent Mg(2)Mg4Sn8 cuboctahedra, and faces with two equivalent Sn(3)Mg6 cuboctahedra. In the fourth Sn site, Sn(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Sn(2), two equivalent Sn(4), and four equivalent Sn(1) atoms to form distorted SnMg4Sn8 cuboctahedra that share corners with six equivalent Mg(1)Mg4Sn8 cuboctahedra, corners with six equivalent Mg(2)Mg4Sn8 cuboctahedra, corners with six equivalent Sn(4)Mg4Sn8 cuboctahedra, corners with eight equivalent Sn(3)Mg6 cuboctahedra, edges with two equivalent Sn(3)Mg6 cuboctahedra, edges with three equivalent Mg(1)Mg4Sn8 cuboctahedra, edges with three equivalent Mg(2)Mg4Sn8 cuboctahedra, faces with two equivalent Mg(1)Mg4Sn8 cuboctahedra, faces with two equivalent Mg(2)Mg4Sn8 cuboctahedra, and faces with four equivalent Sn(4)Mg4Sn8 cuboctahedra. Both Sn(4)-Sn(4) bond lengths are 3.34 Å.