MgLa5 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded in a distorted q6 geometry to two equivalent La(3), two equivalent La(4), two equivalent La(5), and four equivalent La(2) atoms. There are five inequivalent La sites. In the first La site, La(1) is bonded to two equivalent La(1), two equivalent La(2), two equivalent La(3), two equivalent La(5), and four equivalent La(4) atoms to form LaLa12 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(3)La10Mg2 cuboctahedra, edges with three equivalent La(2)La8Mg4 cuboctahedra, edges with four equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(4)La10Mg2 cuboctahedra, faces with four equivalent La(1)La12 cuboctahedra, and faces with six equivalent La(5)La10Mg2 cuboctahedra. In the second La site, La(2) is bonded to four equivalent Mg(1), two equivalent La(1), two equivalent La(2), two equivalent La(3), and two equivalent La(4) atoms to form distorted LaLa8Mg4 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(3)La10Mg2 cuboctahedra, edges with three equivalent La(1)La12 cuboctahedra, edges with eight equivalent La(5)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(5)La10Mg2 cuboctahedra, faces with two equivalent La(1)La12 cuboctahedra, faces with four equivalent La(2)La8Mg4 cuboctahedra, and faces with six equivalent La(4)La10Mg2 cuboctahedra. In the third La site, La(3) is bonded to two equivalent Mg(1), two equivalent La(1), two equivalent La(2), two equivalent La(3), and four equivalent La(5) atoms to form LaLa10Mg2 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(1)La12 cuboctahedra, edges with three equivalent La(2)La8Mg4 cuboctahedra, edges with four equivalent La(5)La10Mg2 cuboctahedra, edges with eight equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(1)La12 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(3)La10Mg2 cuboctahedra, and faces with four equivalent La(5)La10Mg2 cuboctahedra. In the fourth La site, La(4) is bonded to two equivalent Mg(1), two equivalent La(2), two equivalent La(4), two equivalent La(5), and four equivalent La(1) atoms to form distorted LaLa10Mg2 cuboctahedra that share corners with six equivalent La(4)La10Mg2 cuboctahedra, corners with six equivalent La(5)La10Mg2 cuboctahedra, edges with three equivalent La(5)La10Mg2 cuboctahedra, edges with four equivalent La(1)La12 cuboctahedra, edges with eight equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(5)La10Mg2 cuboctahedra, faces with four equivalent La(4)La10Mg2 cuboctahedra, faces with four equivalent La(1)La12 cuboctahedra, and faces with six equivalent La(2)La8Mg4 cuboctahedra. In the fifth La site, La(5) is bonded to two equivalent Mg(1), two equivalent La(1), two equivalent La(4), two equivalent La(5), and four equivalent La(3) atoms to form distorted LaLa10Mg2 cuboctahedra that share corners with six equivalent La(4)La10Mg2 cuboctahedra, corners with six equivalent La(5)La10Mg2 cuboctahedra, edges with three equivalent La(4)La10Mg2 cuboctahedra, edges with four equivalent La(3)La10Mg2 cuboctahedra, edges with eight equivalent La(2)La8Mg4 cuboctahedra, faces with two equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(3)La10Mg2 cuboctahedra, faces with four equivalent La(5)La10Mg2 cuboctahedra, and faces with six equivalent La(1)La12 cuboctahedra.
MgLa5 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded in a distorted q6 geometry to two equivalent La(3), two equivalent La(4), two equivalent La(5), and four equivalent La(2) atoms. Both Mg(1)-La(3) bond lengths are 3.65 Å. Both Mg(1)-La(4) bond lengths are 3.61 Å. Both Mg(1)-La(5) bond lengths are 3.51 Å. All Mg(1)-La(2) bond lengths are 3.63 Å. There are five inequivalent La sites. In the first La site, La(1) is bonded to two equivalent La(1), two equivalent La(2), two equivalent La(3), two equivalent La(5), and four equivalent La(4) atoms to form LaLa12 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(3)La10Mg2 cuboctahedra, edges with three equivalent La(2)La8Mg4 cuboctahedra, edges with four equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(4)La10Mg2 cuboctahedra, faces with four equivalent La(1)La12 cuboctahedra, and faces with six equivalent La(5)La10Mg2 cuboctahedra. Both La(1)-La(1) bond lengths are 3.73 Å. Both La(1)-La(2) bond lengths are 3.67 Å. Both La(1)-La(3) bond lengths are 3.76 Å. Both La(1)-La(5) bond lengths are 3.83 Å. All La(1)-La(4) bond lengths are 3.65 Å. In the second La site, La(2) is bonded to four equivalent Mg(1), two equivalent La(1), two equivalent La(2), two equivalent La(3), and two equivalent La(4) atoms to form distorted LaLa8Mg4 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(3)La10Mg2 cuboctahedra, edges with three equivalent La(1)La12 cuboctahedra, edges with eight equivalent La(5)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(5)La10Mg2 cuboctahedra, faces with two equivalent La(1)La12 cuboctahedra, faces with four equivalent La(2)La8Mg4 cuboctahedra, and faces with six equivalent La(4)La10Mg2 cuboctahedra. Both La(2)-La(2) bond lengths are 3.73 Å. Both La(2)-La(3) bond lengths are 3.53 Å. Both La(2)-La(4) bond lengths are 3.71 Å. In the third La site, La(3) is bonded to two equivalent Mg(1), two equivalent La(1), two equivalent La(2), two equivalent La(3), and four equivalent La(5) atoms to form LaLa10Mg2 cuboctahedra that share corners with six equivalent La(3)La10Mg2 cuboctahedra, corners with six equivalent La(1)La12 cuboctahedra, corners with six equivalent La(2)La8Mg4 cuboctahedra, edges with three equivalent La(1)La12 cuboctahedra, edges with three equivalent La(2)La8Mg4 cuboctahedra, edges with four equivalent La(5)La10Mg2 cuboctahedra, edges with eight equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(1)La12 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(3)La10Mg2 cuboctahedra, and faces with four equivalent La(5)La10Mg2 cuboctahedra. Both La(3)-La(3) bond lengths are 3.73 Å. All La(3)-La(5) bond lengths are 3.62 Å. In the fourth La site, La(4) is bonded to two equivalent Mg(1), two equivalent La(2), two equivalent La(4), two equivalent La(5), and four equivalent La(1) atoms to form distorted LaLa10Mg2 cuboctahedra that share corners with six equivalent La(4)La10Mg2 cuboctahedra, corners with six equivalent La(5)La10Mg2 cuboctahedra, edges with three equivalent La(5)La10Mg2 cuboctahedra, edges with four equivalent La(1)La12 cuboctahedra, edges with eight equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(3)La10Mg2 cuboctahedra, faces with two equivalent La(5)La10Mg2 cuboctahedra, faces with four equivalent La(4)La10Mg2 cuboctahedra, faces with four equivalent La(1)La12 cuboctahedra, and faces with six equivalent La(2)La8Mg4 cuboctahedra. Both La(4)-La(4) bond lengths are 3.73 Å. Both La(4)-La(5) bond lengths are 3.84 Å. In the fifth La site, La(5) is bonded to two equivalent Mg(1), two equivalent La(1), two equivalent La(4), two equivalent La(5), and four equivalent La(3) atoms to form distorted LaLa10Mg2 cuboctahedra that share corners with six equivalent La(4)La10Mg2 cuboctahedra, corners with six equivalent La(5)La10Mg2 cuboctahedra, edges with three equivalent La(4)La10Mg2 cuboctahedra, edges with four equivalent La(3)La10Mg2 cuboctahedra, edges with eight equivalent La(2)La8Mg4 cuboctahedra, faces with two equivalent La(4)La10Mg2 cuboctahedra, faces with two equivalent La(2)La8Mg4 cuboctahedra, faces with four equivalent La(3)La10Mg2 cuboctahedra, faces with four equivalent La(5)La10Mg2 cuboctahedra, and faces with six equivalent La(1)La12 cuboctahedra. Both La(5)-La(5) bond lengths are 3.73 Å.