Eu11(ZnAs2)6 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic C2/m space group. There are six inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 12-coordinate geometry to two equivalent Zn(2), two equivalent Zn(3), one As(1), one As(2), two equivalent As(4), and four equivalent As(5) atoms. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one Zn(1), one As(1), one As(2), two equivalent As(3), and two equivalent As(5) atoms. In the third Eu site, Eu(3) is bonded to one As(1), one As(2), two equivalent As(4), and two equivalent As(6) atoms to form a mixture of distorted corner, edge, and face-sharing EuAs6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the fourth Eu site, Eu(4) is bonded in a 6-coordinate geometry to one As(1), two equivalent As(6), and three equivalent As(3) atoms. In the fifth Eu site, Eu(5) is bonded in a 7-coordinate geometry to two equivalent Zn(1), two equivalent As(2), and three equivalent As(6) atoms. In the sixth Eu site, Eu(6) is bonded to two equivalent As(1) and four equivalent As(4) atoms to form a mixture of distorted corner, edge, and face-sharing EuAs6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are three inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 3-coordinate geometry to one Eu(2), two equivalent Eu(5), one As(2), one As(6), and two equivalent As(3) atoms. In the second Zn site, Zn(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1), one As(4), one As(5), and two equivalent As(2) atoms. In the third Zn site, Zn(3) is bonded in a distorted trigonal planar geometry to two equivalent Eu(1), one As(4), and two equivalent As(1) atoms. There are six inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), one Eu(4), one Eu(6), and two equivalent Zn(3) atoms. In the second As site, As(2) is bonded in a 7-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), two equivalent Eu(5), one Zn(1), and two equivalent Zn(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Eu(2), three equivalent Eu(4), and two equivalent Zn(1) atoms. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(3), two equivalent Eu(6), one Zn(2), and one Zn(3) atom. In the fifth As site, As(5) is bonded in a 8-coordinate geometry to two equivalent Eu(2), four equivalent Eu(1), one Zn(2), and one As(5) atom. In the sixth As site, As(6) is bonded in a 8-coordinate geometry to two equivalent Eu(3), two equivalent Eu(4), three equivalent Eu(5), and one Zn(1) atom.
Eu11(ZnAs2)6 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic C2/m space group. There are six inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 12-coordinate geometry to two equivalent Zn(2), two equivalent Zn(3), one As(1), one As(2), two equivalent As(4), and four equivalent As(5) atoms. Both Eu(1)-Zn(2) bond lengths are 3.18 Å. Both Eu(1)-Zn(3) bond lengths are 3.28 Å. The Eu(1)-As(1) bond length is 3.56 Å. The Eu(1)-As(2) bond length is 3.63 Å. Both Eu(1)-As(4) bond lengths are 3.09 Å. There are two shorter (3.16 Å) and two longer (3.18 Å) Eu(1)-As(5) bond lengths. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one Zn(1), one As(1), one As(2), two equivalent As(3), and two equivalent As(5) atoms. The Eu(2)-Zn(1) bond length is 3.11 Å. The Eu(2)-As(1) bond length is 3.03 Å. The Eu(2)-As(2) bond length is 2.98 Å. Both Eu(2)-As(3) bond lengths are 3.16 Å. Both Eu(2)-As(5) bond lengths are 3.01 Å. In the third Eu site, Eu(3) is bonded to one As(1), one As(2), two equivalent As(4), and two equivalent As(6) atoms to form a mixture of distorted corner, edge, and face-sharing EuAs6 octahedra. The corner-sharing octahedral tilt angles are 54°. The Eu(3)-As(1) bond length is 3.15 Å. The Eu(3)-As(2) bond length is 3.01 Å. Both Eu(3)-As(4) bond lengths are 3.26 Å. Both Eu(3)-As(6) bond lengths are 3.22 Å. In the fourth Eu site, Eu(4) is bonded in a 6-coordinate geometry to one As(1), two equivalent As(6), and three equivalent As(3) atoms. The Eu(4)-As(1) bond length is 3.19 Å. Both Eu(4)-As(6) bond lengths are 3.27 Å. There is one shorter (3.07 Å) and two longer (3.21 Å) Eu(4)-As(3) bond lengths. In the fifth Eu site, Eu(5) is bonded in a 7-coordinate geometry to two equivalent Zn(1), two equivalent As(2), and three equivalent As(6) atoms. Both Eu(5)-Zn(1) bond lengths are 3.14 Å. Both Eu(5)-As(2) bond lengths are 3.00 Å. There are two shorter (3.14 Å) and one longer (3.41 Å) Eu(5)-As(6) bond length. In the sixth Eu site, Eu(6) is bonded to two equivalent As(1) and four equivalent As(4) atoms to form a mixture of distorted corner, edge, and face-sharing EuAs6 octahedra. The corner-sharing octahedral tilt angles are 54°. Both Eu(6)-As(1) bond lengths are 3.10 Å. All Eu(6)-As(4) bond lengths are 3.12 Å. There are three inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a 3-coordinate geometry to one Eu(2), two equivalent Eu(5), one As(2), one As(6), and two equivalent As(3) atoms. The Zn(1)-As(2) bond length is 2.96 Å. The Zn(1)-As(6) bond length is 2.51 Å. Both Zn(1)-As(3) bond lengths are 2.56 Å. In the second Zn site, Zn(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1), one As(4), one As(5), and two equivalent As(2) atoms. The Zn(2)-As(4) bond length is 2.55 Å. The Zn(2)-As(5) bond length is 2.76 Å. Both Zn(2)-As(2) bond lengths are 2.52 Å. In the third Zn site, Zn(3) is bonded in a distorted trigonal planar geometry to two equivalent Eu(1), one As(4), and two equivalent As(1) atoms. The Zn(3)-As(4) bond length is 2.65 Å. Both Zn(3)-As(1) bond lengths are 2.45 Å. There are six inequivalent As sites. In the first As site, As(1) is bonded in a 6-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), one Eu(4), one Eu(6), and two equivalent Zn(3) atoms. In the second As site, As(2) is bonded in a 7-coordinate geometry to one Eu(1), one Eu(2), one Eu(3), two equivalent Eu(5), one Zn(1), and two equivalent Zn(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Eu(2), three equivalent Eu(4), and two equivalent Zn(1) atoms. In the fourth As site, As(4) is bonded in a 8-coordinate geometry to two equivalent Eu(1), two equivalent Eu(3), two equivalent Eu(6), one Zn(2), and one Zn(3) atom. In the fifth As site, As(5) is bonded in a 8-coordinate geometry to two equivalent Eu(2), four equivalent Eu(1), one Zn(2), and one As(5) atom. The As(5)-As(5) bond length is 2.49 Å. In the sixth As site, As(6) is bonded in a 8-coordinate geometry to two equivalent Eu(3), two equivalent Eu(4), three equivalent Eu(5), and one Zn(1) atom.