Mg2Y is beta-derived structured and 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), four equivalent Mg(4), and two equivalent Y(2) atoms to form MgY2Mg10 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(3)Y6Mg6 cuboctahedra, edges with four equivalent Mg(4)Y4Mg8 cuboctahedra, edges with eight equivalent Y(1)Y4Mg8 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with four equivalent Mg(1)Y2Mg10 cuboctahedra, faces with four equivalent Mg(4)Y4Mg8 cuboctahedra, and faces with six equivalent Y(2)Y4Mg8 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Y(1) atoms to form MgY4Mg8 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(1)Y2Mg10 cuboctahedra, edges with three equivalent Mg(3)Y6Mg6 cuboctahedra, edges with four equivalent Y(1)Y4Mg8 cuboctahedra, edges with eight equivalent Y(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(2)Y4Mg8 cuboctahedra, faces with four equivalent Y(1)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(4)Y4Mg8 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Y(1), and four equivalent Y(2) atoms to form MgY6Mg6 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(1)Y2Mg10 cuboctahedra, edges with three equivalent Mg(2)Y4Mg8 cuboctahedra, edges with four equivalent Y(2)Y4Mg8 cuboctahedra, edges with eight equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with four equivalent Mg(3)Y6Mg6 cuboctahedra, faces with four equivalent Y(2)Y4Mg8 cuboctahedra, and faces with six equivalent Y(1)Y4Mg8 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), two equivalent Y(1), and two equivalent Y(2) atoms to form MgY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Y(1)Y4Mg8 cuboctahedra, edges with three equivalent Y(2)Y4Mg8 cuboctahedra, edges with four equivalent Mg(1)Y2Mg10 cuboctahedra, edges with eight equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(1)Y2Mg10 cuboctahedra, faces with four equivalent Mg(4)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(2)Y4Mg8 cuboctahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(2), two equivalent Y(1), and two equivalent Y(2) atoms to form YY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(4)Y4Mg8 cuboctahedra, edges with three equivalent Y(2)Y4Mg8 cuboctahedra, edges with four equivalent Mg(2)Y4Mg8 cuboctahedra, edges with eight equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(2)Y4Mg8 cuboctahedra, faces with four equivalent Y(1)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(3)Y6Mg6 cuboctahedra. In the second Y site, Y(2) is bonded to two equivalent Mg(1), two equivalent Mg(4), four equivalent Mg(3), two equivalent Y(1), and two equivalent Y(2) atoms to form YY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(4)Y4Mg8 cuboctahedra, edges with three equivalent Y(1)Y4Mg8 cuboctahedra, edges with four equivalent Mg(3)Y6Mg6 cuboctahedra, edges with eight equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with four equivalent Mg(3)Y6Mg6 cuboctahedra, faces with four equivalent Y(2)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(1)Y2Mg10 cuboctahedra.
Mg2Y is beta-derived structured and 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), four equivalent Mg(4), and two equivalent Y(2) atoms to form MgY2Mg10 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(3)Y6Mg6 cuboctahedra, edges with four equivalent Mg(4)Y4Mg8 cuboctahedra, edges with eight equivalent Y(1)Y4Mg8 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with four equivalent Mg(1)Y2Mg10 cuboctahedra, faces with four equivalent Mg(4)Y4Mg8 cuboctahedra, and faces with six equivalent Y(2)Y4Mg8 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.38 Å. Both Mg(1)-Mg(2) bond lengths are 3.33 Å. Both Mg(1)-Mg(3) bond lengths are 3.44 Å. All Mg(1)-Mg(4) bond lengths are 3.34 Å. Both Mg(1)-Y(2) bond lengths are 3.34 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Y(1) atoms to form MgY4Mg8 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(1)Y2Mg10 cuboctahedra, edges with three equivalent Mg(3)Y6Mg6 cuboctahedra, edges with four equivalent Y(1)Y4Mg8 cuboctahedra, edges with eight equivalent Y(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(2)Y4Mg8 cuboctahedra, faces with four equivalent Y(1)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(4)Y4Mg8 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.38 Å. Both Mg(2)-Mg(3) bond lengths are 3.35 Å. Both Mg(2)-Mg(4) bond lengths are 3.33 Å. All Mg(2)-Y(1) bond lengths are 3.33 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Y(1), and four equivalent Y(2) atoms to form MgY6Mg6 cuboctahedra that share corners with six equivalent Mg(1)Y2Mg10 cuboctahedra, corners with six equivalent Mg(2)Y4Mg8 cuboctahedra, corners with six equivalent Mg(3)Y6Mg6 cuboctahedra, edges with three equivalent Mg(1)Y2Mg10 cuboctahedra, edges with three equivalent Mg(2)Y4Mg8 cuboctahedra, edges with four equivalent Y(2)Y4Mg8 cuboctahedra, edges with eight equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with four equivalent Mg(3)Y6Mg6 cuboctahedra, faces with four equivalent Y(2)Y4Mg8 cuboctahedra, and faces with six equivalent Y(1)Y4Mg8 cuboctahedra. Both Mg(3)-Mg(3) bond lengths are 3.38 Å. Both Mg(3)-Y(1) bond lengths are 3.38 Å. All Mg(3)-Y(2) bond lengths are 3.38 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), two equivalent Mg(4), four equivalent Mg(1), two equivalent Y(1), and two equivalent Y(2) atoms to form MgY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Y(1)Y4Mg8 cuboctahedra, edges with three equivalent Y(2)Y4Mg8 cuboctahedra, edges with four equivalent Mg(1)Y2Mg10 cuboctahedra, edges with eight equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Mg(3)Y6Mg6 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(1)Y2Mg10 cuboctahedra, faces with four equivalent Mg(4)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(2)Y4Mg8 cuboctahedra. Both Mg(4)-Mg(4) bond lengths are 3.38 Å. Both Mg(4)-Y(1) bond lengths are 3.28 Å. Both Mg(4)-Y(2) bond lengths are 3.33 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(2), two equivalent Y(1), and two equivalent Y(2) atoms to form YY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(4)Y4Mg8 cuboctahedra, edges with three equivalent Y(2)Y4Mg8 cuboctahedra, edges with four equivalent Mg(2)Y4Mg8 cuboctahedra, edges with eight equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(1)Y2Mg10 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Y(2)Y4Mg8 cuboctahedra, faces with four equivalent Mg(2)Y4Mg8 cuboctahedra, faces with four equivalent Y(1)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(3)Y6Mg6 cuboctahedra. Both Y(1)-Y(1) bond lengths are 3.38 Å. Both Y(1)-Y(2) bond lengths are 3.50 Å. In the second Y site, Y(2) is bonded to two equivalent Mg(1), two equivalent Mg(4), four equivalent Mg(3), two equivalent Y(1), and two equivalent Y(2) atoms to form YY4Mg8 cuboctahedra that share corners with six equivalent Mg(4)Y4Mg8 cuboctahedra, corners with six equivalent Y(1)Y4Mg8 cuboctahedra, corners with six equivalent Y(2)Y4Mg8 cuboctahedra, edges with three equivalent Mg(4)Y4Mg8 cuboctahedra, edges with three equivalent Y(1)Y4Mg8 cuboctahedra, edges with four equivalent Mg(3)Y6Mg6 cuboctahedra, edges with eight equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(2)Y4Mg8 cuboctahedra, faces with two equivalent Mg(4)Y4Mg8 cuboctahedra, faces with two equivalent Y(1)Y4Mg8 cuboctahedra, faces with four equivalent Mg(3)Y6Mg6 cuboctahedra, faces with four equivalent Y(2)Y4Mg8 cuboctahedra, and faces with six equivalent Mg(1)Y2Mg10 cuboctahedra. Both Y(2)-Y(2) bond lengths are 3.38 Å.