Mg6AlB crystallizes in the orthorhombic Amm2 space group. There are seven 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 Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Al2 cuboctahedra; corners with ten Mg(1,1)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(2)Mg10Al2 cuboctahedra; edges with two equivalent Mg(1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Al(1) atoms to form distorted MgMg10Al2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Al2 cuboctahedra; corners with eight Mg(1,1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four Mg(1,1)Mg8Al2B2 cuboctahedra; edges with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(1,1)Mg8Al2B2 cuboctahedra; and faces with four equivalent Mg(3)Mg8Al2B2 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 Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2); four equivalent Mg(1); four Mg(3,3,3); and two equivalent B(1) atoms to form distorted MgMg10B2 cuboctahedra that share corners with six equivalent Mg(4)Mg10B2 cuboctahedra; corners with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with eight Mg(1,1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with four Mg(3,3,3)Mg8Al2B2 cuboctahedra. In the fifth 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 Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Al2 cuboctahedra; corners with ten Mg(1,1)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(2)Mg10Al2 cuboctahedra; edges with two equivalent Mg(1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with eight Mg(3,3)Mg8Al2B2 cuboctahedra. In the sixth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(3,3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. In the seventh Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(3,3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. Al(1) is bonded in a distorted q6 geometry to two equivalent Mg(2); four Mg(1,1); and four equivalent Mg(3) atoms. B(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4); four equivalent Mg(1); and four Mg(3,3,3) atoms.
Mg6AlB crystallizes in the orthorhombic Amm2 space group. There are seven 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 Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Al2 cuboctahedra; corners with ten Mg(1,1)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(2)Mg10Al2 cuboctahedra; edges with two equivalent Mg(1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra. There is one shorter (2.87 Å) and one longer (3.11 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.00 Å) and one longer (3.03 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.09 Å. Both Mg(1)-Mg(4) bond lengths are 3.04 Å. There is one shorter (2.92 Å) and one longer (3.11 Å) Mg(1)-Al(1) bond length. Both Mg(1)-B(1) bond lengths are 2.97 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(1,1); four equivalent Mg(3); and two equivalent Al(1) atoms to form distorted MgMg10Al2 cuboctahedra that share corners with six equivalent Mg(2)Mg10Al2 cuboctahedra; corners with eight Mg(1,1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four Mg(1,1)Mg8Al2B2 cuboctahedra; edges with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(1,1)Mg8Al2B2 cuboctahedra; and faces with four equivalent Mg(3)Mg8Al2B2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.04 Å. Both Mg(2)-Mg(1) bond lengths are 3.03 Å. All Mg(2)-Mg(3) bond lengths are 3.02 Å. Both Mg(2)-Al(1) bond lengths are 2.99 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 Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. Both Mg(3)-Mg(1) bond lengths are 3.09 Å. There is one shorter (2.95 Å) and one longer (3.04 Å) Mg(3)-Mg(3) bond length. There is one shorter (2.99 Å) and one longer (3.03 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Al(1) bond lengths are 3.00 Å. There is one shorter (2.98 Å) and one longer (3.05 Å) Mg(3)-B(1) bond length. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2); four equivalent Mg(1); four Mg(3,3,3); and two equivalent B(1) atoms to form distorted MgMg10B2 cuboctahedra that share corners with six equivalent Mg(4)Mg10B2 cuboctahedra; corners with eight Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with eight Mg(1,1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with four Mg(3,3,3)Mg8Al2B2 cuboctahedra. Both Mg(4)-Mg(3,3) bond lengths are 3.03 Å. Both Mg(4)-B(1) bond lengths are 2.99 Å. In the fifth 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 Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Al2 cuboctahedra; corners with ten Mg(1,1)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(2)Mg10Al2 cuboctahedra; edges with two equivalent Mg(1)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(4)Mg10B2 cuboctahedra; edges with four equivalent Mg(3)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; and faces with eight Mg(3,3)Mg8Al2B2 cuboctahedra. There is one shorter (2.87 Å) and one longer (3.11 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(4) bond lengths are 3.04 Å. There is one shorter (2.92 Å) and one longer (3.11 Å) Mg(1)-Al(1) bond length. Both Mg(1)-B(1) bond lengths are 2.97 Å. In the sixth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(3,3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. Both Mg(3)-Mg(2) bond lengths are 3.02 Å. There is one shorter (2.95 Å) and one longer (3.04 Å) Mg(3)-Mg(3) bond length. Both Mg(3)-Al(1) bond lengths are 3.00 Å. There is one shorter (2.98 Å) and one longer (3.05 Å) Mg(3)-B(1) bond length. In the seventh Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Al(1), and two equivalent B(1) atoms to form distorted MgMg8Al2B2 cuboctahedra that share corners with four equivalent Mg(4)Mg10B2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Al2B2 cuboctahedra; edges with two equivalent Mg(4)Mg10B2 cuboctahedra; edges with two equivalent Mg(3)Mg8Al2B2 cuboctahedra; edges with four equivalent Mg(2)Mg10Al2 cuboctahedra; edges with four equivalent Mg(1)Mg8Al2B2 cuboctahedra; faces with two equivalent Mg(2)Mg10Al2 cuboctahedra; faces with two equivalent Mg(4)Mg10B2 cuboctahedra; faces with four Mg(3,3)Mg8Al2B2 cuboctahedra; and faces with eight Mg(1,1)Mg8Al2B2 cuboctahedra. Both Mg(3)-Mg(1) bond lengths are 3.09 Å. Both Mg(3)-Mg(2) bond lengths are 3.02 Å. Both Mg(3)-Al(1) bond lengths are 3.00 Å. There is one shorter (2.98 Å) and one longer (3.05 Å) Mg(3)-B(1) bond length. Al(1) is bonded in a distorted q6 geometry to two equivalent Mg(2); four Mg(1,1); and four equivalent Mg(3) atoms. B(1) is bonded in a 10-coordinate geometry to two equivalent Mg(4); four equivalent Mg(1); and four Mg(3,3,3) atoms.