Eu2(NiZn)5 crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 18-coordinate geometry to two equivalent Ni(1), four equivalent Ni(2), four equivalent Zn(1), and eight equivalent Zn(2) atoms. In the second Eu site, Eu(2) is bonded in a 18-coordinate geometry to two equivalent Ni(2), four equivalent Ni(1), four equivalent Ni(3), and eight equivalent Zn(2) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to one Eu(1), two equivalent Eu(2), two equivalent Ni(3), and four equivalent Zn(2) atoms. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to one Eu(2), two equivalent Eu(1), two equivalent Zn(1), and four equivalent Zn(2) atoms. In the third Ni site, Ni(3) is bonded to four equivalent Eu(2), four equivalent Ni(1), and four equivalent Zn(2) atoms to form distorted NiEu4Zn4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with four equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, edges with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, and faces with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to four equivalent Eu(1), four equivalent Ni(2), and four equivalent Zn(2) atoms to form distorted ZnEu4Zn4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with four equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, edges with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, and faces with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra. In the second Zn site, Zn(2) is bonded to two equivalent Eu(1), two equivalent Eu(2), one Ni(3), two equivalent Ni(1), two equivalent Ni(2), one Zn(1), and two equivalent Zn(2) atoms to form distorted ZnEu4Zn3Ni5 cuboctahedra that share corners with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with twelve equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, edges with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, edges with six equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, faces with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, and faces with six equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra.
Eu2(NiZn)5 crystallizes in the orthorhombic Pmmm space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 18-coordinate geometry to two equivalent Ni(1), four equivalent Ni(2), four equivalent Zn(1), and eight equivalent Zn(2) atoms. Both Eu(1)-Ni(1) bond lengths are 3.06 Å. All Eu(1)-Ni(2) bond lengths are 3.02 Å. All Eu(1)-Zn(1) bond lengths are 3.28 Å. All Eu(1)-Zn(2) bond lengths are 3.29 Å. In the second Eu site, Eu(2) is bonded in a 18-coordinate geometry to two equivalent Ni(2), four equivalent Ni(1), four equivalent Ni(3), and eight equivalent Zn(2) atoms. Both Eu(2)-Ni(2) bond lengths are 2.98 Å. All Eu(2)-Ni(1) bond lengths are 2.98 Å. All Eu(2)-Ni(3) bond lengths are 3.28 Å. All Eu(2)-Zn(2) bond lengths are 3.22 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to one Eu(1), two equivalent Eu(2), two equivalent Ni(3), and four equivalent Zn(2) atoms. Both Ni(1)-Ni(3) bond lengths are 2.42 Å. All Ni(1)-Zn(2) bond lengths are 2.48 Å. In the second Ni site, Ni(2) is bonded in a 9-coordinate geometry to one Eu(2), two equivalent Eu(1), two equivalent Zn(1), and four equivalent Zn(2) atoms. Both Ni(2)-Zn(1) bond lengths are 2.47 Å. All Ni(2)-Zn(2) bond lengths are 2.51 Å. In the third Ni site, Ni(3) is bonded to four equivalent Eu(2), four equivalent Ni(1), and four equivalent Zn(2) atoms to form distorted NiEu4Zn4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with four equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, edges with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, and faces with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra. All Ni(3)-Zn(2) bond lengths are 2.53 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to four equivalent Eu(1), four equivalent Ni(2), and four equivalent Zn(2) atoms to form distorted ZnEu4Zn4Ni4 cuboctahedra that share corners with four equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with four equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, edges with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, and faces with eight equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra. All Zn(1)-Zn(2) bond lengths are 2.65 Å. In the second Zn site, Zn(2) is bonded to two equivalent Eu(1), two equivalent Eu(2), one Ni(3), two equivalent Ni(1), two equivalent Ni(2), one Zn(1), and two equivalent Zn(2) atoms to form distorted ZnEu4Zn3Ni5 cuboctahedra that share corners with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, corners with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, corners with twelve equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, edges with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, edges with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, edges with six equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra, faces with two equivalent Ni(3)Eu4Zn4Ni4 cuboctahedra, faces with two equivalent Zn(1)Eu4Zn4Ni4 cuboctahedra, and faces with six equivalent Zn(2)Eu4Zn3Ni5 cuboctahedra. There is one shorter (2.60 Å) and one longer (2.66 Å) Zn(2)-Zn(2) bond length.