Mg6FeNi 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), two equivalent Mg(4), two equivalent Fe(1), and two equivalent Ni(1) atoms to form distorted MgMg8Fe2Ni2 cuboctahedra that share corners with four equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with four equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with two equivalent Ni(1)Mg10Fe2 cuboctahedra, edges with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Fe2Ni2 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), two equivalent Fe(1), and two equivalent Ni(1) atoms to form distorted MgMg8Fe2Ni2 cuboctahedra that share corners with ten equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with four equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with four equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to four equivalent Mg(1), four equivalent Mg(2), and two equivalent Fe(1) atoms. In the fourth Mg site, Mg(4) is bonded in a distorted water-like geometry to four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ni(1) atoms. Fe(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ni(1) atoms to form distorted FeMg10Ni2 cuboctahedra that share corners with four equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with six equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Ni(1)Mg10Fe2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra. Ni(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Fe(1) atoms to form distorted NiMg10Fe2 cuboctahedra that share corners with four equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with six equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra.
Mg6FeNi 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), two equivalent Mg(4), two equivalent Fe(1), and two equivalent Ni(1) atoms to form distorted MgMg8Fe2Ni2 cuboctahedra that share corners with four equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with four equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with ten equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with two equivalent Ni(1)Mg10Fe2 cuboctahedra, edges with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra. There is one shorter (3.01 Å) and one longer (3.04 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 2.91 Å. Both Mg(1)-Mg(3) bond lengths are 2.91 Å. Both Mg(1)-Mg(4) bond lengths are 2.91 Å. There is one shorter (2.92 Å) and one longer (2.97 Å) Mg(1)-Fe(1) bond length. There is one shorter (2.93 Å) and one longer (2.95 Å) Mg(1)-Ni(1) bond length. 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), two equivalent Fe(1), and two equivalent Ni(1) atoms to form distorted MgMg8Fe2Ni2 cuboctahedra that share corners with ten equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with four equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with four equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra. There is one shorter (2.98 Å) and one longer (3.06 Å) Mg(2)-Mg(2) bond length. There is one shorter (2.78 Å) and one longer (3.10 Å) Mg(2)-Mg(3) bond length. There is one shorter (2.80 Å) and one longer (3.08 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Fe(1) bond lengths are 2.85 Å. Both Mg(2)-Ni(1) bond lengths are 2.87 Å. In the third Mg site, Mg(3) is bonded in a 2-coordinate geometry to four equivalent Mg(1), four equivalent Mg(2), and two equivalent Fe(1) atoms. Both Mg(3)-Fe(1) bond lengths are 2.79 Å. In the fourth Mg site, Mg(4) is bonded in a distorted water-like geometry to four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ni(1) atoms. Both Mg(4)-Ni(1) bond lengths are 2.80 Å. Fe(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Ni(1) atoms to form distorted FeMg10Ni2 cuboctahedra that share corners with four equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with six equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Ni(1)Mg10Fe2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra. Both Fe(1)-Ni(1) bond lengths are 3.02 Å. Ni(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Fe(1) atoms to form distorted NiMg10Fe2 cuboctahedra that share corners with four equivalent Fe(1)Mg10Ni2 cuboctahedra, corners with six equivalent Ni(1)Mg10Fe2 cuboctahedra, corners with eight equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with two equivalent Fe(1)Mg10Ni2 cuboctahedra, edges with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, edges with eight equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra, faces with two equivalent Fe(1)Mg10Ni2 cuboctahedra, faces with two equivalent Ni(1)Mg10Fe2 cuboctahedra, faces with four equivalent Mg(1)Mg8Fe2Ni2 cuboctahedra, and faces with four equivalent Mg(2)Mg8Fe2Ni2 cuboctahedra.