Er4Fe34C3 crystallizes in the triclinic P-1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Fe(15), one Fe(17), one Fe(18), two equivalent Fe(13), three equivalent Fe(7), one C(1), and one C(2) atom. In the second Er site, Er(2) is bonded in a distorted single-bond geometry to one Fe(16), one Fe(17), one Fe(18), one Fe(2), two equivalent Fe(12), two equivalent Fe(14), three equivalent Fe(6), three equivalent Fe(8), and one C(1) atom. There are eighteen inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Er(1), one Fe(10), one Fe(11), one Fe(12), one Fe(13), one Fe(14), one Fe(15), one Fe(17), one Fe(18), one Fe(2), one Fe(4), one Fe(5), one Fe(7), and one Fe(9) atom. In the second Fe site, Fe(2) is bonded in a 14-coordinate geometry to one Er(2), one Fe(1), one Fe(10), one Fe(11), one Fe(12), one Fe(13), one Fe(14), one Fe(16), one Fe(17), one Fe(18), one Fe(3), one Fe(6), one Fe(8), and one Fe(9) atom. In the third Fe site, Fe(3) is bonded in a single-bond geometry to one Fe(13), one Fe(17), one Fe(18), one Fe(2), one Fe(7), and one C(1) atom. In the fourth Fe site, Fe(4) is bonded in a single-bond geometry to one Fe(1), one Fe(12), one Fe(14), one Fe(17), one Fe(18), one Fe(6), one Fe(8), and one C(1) atom. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to one Fe(1), one Fe(13), one Fe(15), one Fe(18), one Fe(7), and one C(2) atom. In the sixth Fe site, Fe(6) is bonded to three equivalent Er(2), one Fe(14), one Fe(16), one Fe(18), one Fe(2), one Fe(4), one Fe(8), one Fe(9), and two equivalent Fe(12) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(18)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with three equivalent Fe(17)Er2Fe10 cuboctahedra, corners with three equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra, edges with two equivalent Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra, faces with three equivalent Fe(14)Er2Fe10 cuboctahedra, faces with three equivalent Fe(8)Er3Fe9 cuboctahedra, and  a faceface with one C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 66-70°. In the seventh Fe site, Fe(7) is bonded to three equivalent Er(1), one Fe(1), one Fe(11), one Fe(15), one Fe(17), one Fe(3), one Fe(5), one Fe(9), and two equivalent Fe(13) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(6)Er3Fe9 cuboctahedra,  a cornercorner with one Fe(8)Er3Fe9 cuboctahedra, corners with three equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, corners with two equivalent C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(15)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one C(1)Er2Fe4 octahedra, and  a faceface with one C(2)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-69°. In the eighth Fe site, Fe(8) is bonded to three equivalent Er(2), one Fe(10), one Fe(12), one Fe(16), one Fe(17), one Fe(2), one Fe(4), one Fe(6), and two equivalent Fe(14) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with three equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra, edges with two equivalent Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with three equivalent Fe(14)Er2Fe10 cuboctahedra, faces with three equivalent Fe(6)Er3Fe9 cuboctahedra, and  a faceface with one C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 65-69°. In the ninth Fe site, Fe(9) is bonded in a single-bond geometry to one Fe(1), one Fe(14), one Fe(17), one Fe(18), one Fe(2), one Fe(6), one Fe(7), and one C(1) atom. In the tenth Fe site, Fe(10) is bonded in a single-bond geometry to one Fe(1), one Fe(12), one Fe(13), one Fe(17), one Fe(18), one Fe(2), one Fe(8), and one C(1) atom. In the eleventh Fe site, Fe(11) is bonded in a single-bond geometry to one Fe(1), one Fe(13), one Fe(15), one Fe(18), one Fe(2), one Fe(7), and one C(2) atom. In the twelfth Fe site, Fe(12) is bonded in a 12-coordinate geometry to two equivalent Er(2), one Fe(1), one Fe(10), one Fe(14), one Fe(16), one Fe(18), one Fe(2), one Fe(4), one Fe(8), and two equivalent Fe(6) atoms. In the thirteenth Fe site, Fe(13) is bonded in a 12-coordinate geometry to two equivalent Er(1), one Fe(1), one Fe(10), one Fe(11), one Fe(15), one Fe(17), one Fe(2), one Fe(3), one Fe(5), and two equivalent Fe(7) atoms. In the fourteenth Fe site, Fe(14) is bonded to two equivalent Er(2), one Fe(1), one Fe(12), one Fe(16), one Fe(17), one Fe(2), one Fe(4), one Fe(6), one Fe(9), and two equivalent Fe(8) atoms to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(14)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one C(1)Er2Fe4 octahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with three equivalent Fe(6)Er3Fe9 cuboctahedra, and faces with three equivalent Fe(8)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles range from 25-30°. In the fifteenth Fe site, Fe(15) is bonded to two equivalent Er(1), two equivalent Fe(1), two equivalent Fe(11), two equivalent Fe(13), two equivalent Fe(5), and two equivalent Fe(7) atoms to form FeEr2Fe10 cuboctahedra that share corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, edges with two equivalent Fe(7)Er3Fe9 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with two equivalent Fe(7)Er3Fe9 cuboctahedra, and faces with two equivalent C(2)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. In the sixteenth Fe site, Fe(16) is bonded to two equivalent Er(2), two equivalent Fe(12), two equivalent Fe(14), two equivalent Fe(2), two equivalent Fe(6), and two equivalent Fe(8) atoms to form FeEr2Fe10 cuboctahedra that share corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, edges with two equivalent Fe(14)Er2Fe10 cuboctahedra, edges with two equivalent Fe(6)Er3Fe9 cuboctahedra, edges with two equivalent Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(14)Er2Fe10 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with two equivalent Fe(6)Er3Fe9 cuboctahedra, and faces with two equivalent Fe(8)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. In the seventeenth Fe site, Fe(17) is bonded to one Er(1), one Er(2), one Fe(1), one Fe(10), one Fe(13), one Fe(14), one Fe(2), one Fe(3), one Fe(4), one Fe(7), one Fe(8), and one Fe(9) atom to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(14)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra,  a cornercorner with one Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(6)Er3Fe9 cuboctahedra,  a cornercorner with one C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, and faces with two equivalent C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. In the eighteenth Fe site, Fe(18) is bonded to one Er(1), one Er(2), one Fe(1), one Fe(10), one Fe(11), one Fe(12), one Fe(2), one Fe(3), one Fe(4), one Fe(5), one Fe(6), and one Fe(9) atom to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with three equivalent Fe(7)Er3Fe9 cuboctahedra, corners with three equivalent Fe(8)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(14)Er2Fe10 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra,  a faceface with one C(2)Er2Fe4 octahedra, and faces with two equivalent C(1)Er2Fe4 octahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded to one Er(1), one Er(2), one Fe(10), one Fe(3), one Fe(4), and one Fe(9) atom to form CEr2Fe4 octahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra,  a cornercorner with one C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, and faces with two equivalent Fe(18)Er2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. In the second C site, C(2) is bonded to two equivalent Er(1), two equivalent Fe(11), and two equivalent Fe(5) atoms to form CEr2Fe4 octahedra that share corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with four equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, faces with two equivalent Fe(15)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, and faces with two equivalent Fe(7)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 62°.
Er4Fe34C3 crystallizes in the triclinic P-1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Fe(15), one Fe(17), one Fe(18), two equivalent Fe(13), three equivalent Fe(7), one C(1), and one C(2) atom. The Er(1)-Fe(1) bond length is 3.05 Å. The Er(1)-Fe(15) bond length is 3.28 Å. The Er(1)-Fe(17) bond length is 3.28 Å. The Er(1)-Fe(18) bond length is 3.36 Å. There is one shorter (3.03 Å) and one longer (3.04 Å) Er(1)-Fe(13) bond length. There are a spread of Er(1)-Fe(7) bond distances ranging from 3.05-3.34 Å. The Er(1)-C(1) bond length is 2.49 Å. The Er(1)-C(2) bond length is 2.50 Å. In the second Er site, Er(2) is bonded in a distorted single-bond geometry to one Fe(16), one Fe(17), one Fe(18), one Fe(2), two equivalent Fe(12), two equivalent Fe(14), three equivalent Fe(6), three equivalent Fe(8), and one C(1) atom. The Er(2)-Fe(16) bond length is 3.26 Å. The Er(2)-Fe(17) bond length is 3.31 Å. The Er(2)-Fe(18) bond length is 3.31 Å. The Er(2)-Fe(2) bond length is 3.05 Å. There is one shorter (3.00 Å) and one longer (3.08 Å) Er(2)-Fe(12) bond length. There is one shorter (3.02 Å) and one longer (3.06 Å) Er(2)-Fe(14) bond length. There are a spread of Er(2)-Fe(6) bond distances ranging from 3.06-3.29 Å. There are a spread of Er(2)-Fe(8) bond distances ranging from 3.06-3.31 Å. The Er(2)-C(1) bond length is 2.52 Å. There are eighteen inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one Er(1), one Fe(10), one Fe(11), one Fe(12), one Fe(13), one Fe(14), one Fe(15), one Fe(17), one Fe(18), one Fe(2), one Fe(4), one Fe(5), one Fe(7), and one Fe(9) atom. The Fe(1)-Fe(10) bond length is 2.72 Å. The Fe(1)-Fe(11) bond length is 2.73 Å. The Fe(1)-Fe(12) bond length is 2.78 Å. The Fe(1)-Fe(13) bond length is 2.76 Å. The Fe(1)-Fe(14) bond length is 2.77 Å. The Fe(1)-Fe(15) bond length is 2.63 Å. The Fe(1)-Fe(17) bond length is 2.62 Å. The Fe(1)-Fe(18) bond length is 2.64 Å. The Fe(1)-Fe(2) bond length is 2.40 Å. The Fe(1)-Fe(4) bond length is 2.64 Å. The Fe(1)-Fe(5) bond length is 2.64 Å. The Fe(1)-Fe(7) bond length is 2.68 Å. The Fe(1)-Fe(9) bond length is 2.73 Å. In the second Fe site, Fe(2) is bonded in a 14-coordinate geometry to one Er(2), one Fe(1), one Fe(10), one Fe(11), one Fe(12), one Fe(13), one Fe(14), one Fe(16), one Fe(17), one Fe(18), one Fe(3), one Fe(6), one Fe(8), and one Fe(9) atom. The Fe(2)-Fe(10) bond length is 2.72 Å. The Fe(2)-Fe(11) bond length is 2.74 Å. The Fe(2)-Fe(12) bond length is 2.76 Å. The Fe(2)-Fe(13) bond length is 2.77 Å. The Fe(2)-Fe(14) bond length is 2.75 Å. The Fe(2)-Fe(16) bond length is 2.61 Å. The Fe(2)-Fe(17) bond length is 2.62 Å. The Fe(2)-Fe(18) bond length is 2.64 Å. The Fe(2)-Fe(3) bond length is 2.65 Å. The Fe(2)-Fe(6) bond length is 2.66 Å. The Fe(2)-Fe(8) bond length is 2.67 Å. The Fe(2)-Fe(9) bond length is 2.73 Å. In the third Fe site, Fe(3) is bonded in a single-bond geometry to one Fe(13), one Fe(17), one Fe(18), one Fe(2), one Fe(7), and one C(1) atom. The Fe(3)-Fe(13) bond length is 2.56 Å. The Fe(3)-Fe(17) bond length is 2.47 Å. The Fe(3)-Fe(18) bond length is 2.46 Å. The Fe(3)-Fe(7) bond length is 2.53 Å. The Fe(3)-C(1) bond length is 1.92 Å. In the fourth Fe site, Fe(4) is bonded in a single-bond geometry to one Fe(1), one Fe(12), one Fe(14), one Fe(17), one Fe(18), one Fe(6), one Fe(8), and one C(1) atom. The Fe(4)-Fe(12) bond length is 2.56 Å. The Fe(4)-Fe(14) bond length is 2.57 Å. The Fe(4)-Fe(17) bond length is 2.48 Å. The Fe(4)-Fe(18) bond length is 2.47 Å. The Fe(4)-Fe(6) bond length is 2.54 Å. The Fe(4)-Fe(8) bond length is 2.52 Å. The Fe(4)-C(1) bond length is 1.92 Å. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to one Fe(1), one Fe(13), one Fe(15), one Fe(18), one Fe(7), and one C(2) atom. The Fe(5)-Fe(13) bond length is 2.57 Å. The Fe(5)-Fe(15) bond length is 2.47 Å. The Fe(5)-Fe(18) bond length is 2.48 Å. The Fe(5)-Fe(7) bond length is 2.52 Å. The Fe(5)-C(2) bond length is 1.92 Å. In the sixth Fe site, Fe(6) is bonded to three equivalent Er(2), one Fe(14), one Fe(16), one Fe(18), one Fe(2), one Fe(4), one Fe(8), one Fe(9), and two equivalent Fe(12) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(18)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with three equivalent Fe(17)Er2Fe10 cuboctahedra, corners with three equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra, edges with two equivalent Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra, faces with three equivalent Fe(14)Er2Fe10 cuboctahedra, faces with three equivalent Fe(8)Er3Fe9 cuboctahedra, and  a faceface with one C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 66-70°. The Fe(6)-Fe(14) bond length is 2.57 Å. The Fe(6)-Fe(16) bond length is 2.48 Å. The Fe(6)-Fe(18) bond length is 2.47 Å. The Fe(6)-Fe(8) bond length is 2.50 Å. The Fe(6)-Fe(9) bond length is 2.57 Å. There is one shorter (2.60 Å) and one longer (2.63 Å) Fe(6)-Fe(12) bond length. In the seventh Fe site, Fe(7) is bonded to three equivalent Er(1), one Fe(1), one Fe(11), one Fe(15), one Fe(17), one Fe(3), one Fe(5), one Fe(9), and two equivalent Fe(13) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(6)Er3Fe9 cuboctahedra,  a cornercorner with one Fe(8)Er3Fe9 cuboctahedra, corners with three equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, corners with two equivalent C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(15)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one C(1)Er2Fe4 octahedra, and  a faceface with one C(2)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-69°. The Fe(7)-Fe(11) bond length is 2.57 Å. The Fe(7)-Fe(15) bond length is 2.46 Å. The Fe(7)-Fe(17) bond length is 2.47 Å. The Fe(7)-Fe(9) bond length is 2.58 Å. Both Fe(7)-Fe(13) bond lengths are 2.60 Å. In the eighth Fe site, Fe(8) is bonded to three equivalent Er(2), one Fe(10), one Fe(12), one Fe(16), one Fe(17), one Fe(2), one Fe(4), one Fe(6), and two equivalent Fe(14) atoms to form FeEr3Fe9 cuboctahedra that share  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with three equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(18)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra, edges with two equivalent Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(18)Er2Fe10 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with three equivalent Fe(14)Er2Fe10 cuboctahedra, faces with three equivalent Fe(6)Er3Fe9 cuboctahedra, and  a faceface with one C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 65-69°. The Fe(8)-Fe(10) bond length is 2.57 Å. The Fe(8)-Fe(12) bond length is 2.56 Å. The Fe(8)-Fe(16) bond length is 2.46 Å. The Fe(8)-Fe(17) bond length is 2.47 Å. There is one shorter (2.60 Å) and one longer (2.61 Å) Fe(8)-Fe(14) bond length. In the ninth Fe site, Fe(9) is bonded in a single-bond geometry to one Fe(1), one Fe(14), one Fe(17), one Fe(18), one Fe(2), one Fe(6), one Fe(7), and one C(1) atom. The Fe(9)-Fe(14) bond length is 2.48 Å. The Fe(9)-Fe(17) bond length is 2.44 Å. The Fe(9)-Fe(18) bond length is 2.43 Å. The Fe(9)-C(1) bond length is 1.86 Å. In the tenth Fe site, Fe(10) is bonded in a single-bond geometry to one Fe(1), one Fe(12), one Fe(13), one Fe(17), one Fe(18), one Fe(2), one Fe(8), and one C(1) atom. The Fe(10)-Fe(12) bond length is 2.47 Å. The Fe(10)-Fe(13) bond length is 2.48 Å. The Fe(10)-Fe(17) bond length is 2.42 Å. The Fe(10)-Fe(18) bond length is 2.41 Å. The Fe(10)-C(1) bond length is 1.85 Å. In the eleventh Fe site, Fe(11) is bonded in a single-bond geometry to one Fe(1), one Fe(13), one Fe(15), one Fe(18), one Fe(2), one Fe(7), and one C(2) atom. The Fe(11)-Fe(13) bond length is 2.46 Å. The Fe(11)-Fe(15) bond length is 2.43 Å. The Fe(11)-Fe(18) bond length is 2.44 Å. The Fe(11)-C(2) bond length is 1.86 Å. In the twelfth Fe site, Fe(12) is bonded in a 12-coordinate geometry to two equivalent Er(2), one Fe(1), one Fe(10), one Fe(14), one Fe(16), one Fe(18), one Fe(2), one Fe(4), one Fe(8), and two equivalent Fe(6) atoms. The Fe(12)-Fe(14) bond length is 2.51 Å. The Fe(12)-Fe(16) bond length is 2.43 Å. The Fe(12)-Fe(18) bond length is 2.44 Å. In the thirteenth Fe site, Fe(13) is bonded in a 12-coordinate geometry to two equivalent Er(1), one Fe(1), one Fe(10), one Fe(11), one Fe(15), one Fe(17), one Fe(2), one Fe(3), one Fe(5), and two equivalent Fe(7) atoms. The Fe(13)-Fe(15) bond length is 2.44 Å. The Fe(13)-Fe(17) bond length is 2.44 Å. In the fourteenth Fe site, Fe(14) is bonded to two equivalent Er(2), one Fe(1), one Fe(12), one Fe(16), one Fe(17), one Fe(2), one Fe(4), one Fe(6), one Fe(9), and two equivalent Fe(8) atoms to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(14)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra,  an edgeedge with one Fe(16)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(17)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one C(1)Er2Fe4 octahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(17)Er2Fe10 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with three equivalent Fe(6)Er3Fe9 cuboctahedra, and faces with three equivalent Fe(8)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles range from 25-30°. The Fe(14)-Fe(16) bond length is 2.43 Å. The Fe(14)-Fe(17) bond length is 2.44 Å. In the fifteenth Fe site, Fe(15) is bonded to two equivalent Er(1), two equivalent Fe(1), two equivalent Fe(11), two equivalent Fe(13), two equivalent Fe(5), and two equivalent Fe(7) atoms to form FeEr2Fe10 cuboctahedra that share corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, edges with two equivalent Fe(7)Er3Fe9 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with two equivalent Fe(7)Er3Fe9 cuboctahedra, and faces with two equivalent C(2)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. In the sixteenth Fe site, Fe(16) is bonded to two equivalent Er(2), two equivalent Fe(12), two equivalent Fe(14), two equivalent Fe(2), two equivalent Fe(6), and two equivalent Fe(8) atoms to form FeEr2Fe10 cuboctahedra that share corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, edges with two equivalent Fe(14)Er2Fe10 cuboctahedra, edges with two equivalent Fe(6)Er3Fe9 cuboctahedra, edges with two equivalent Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(14)Er2Fe10 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, faces with two equivalent Fe(6)Er3Fe9 cuboctahedra, and faces with two equivalent Fe(8)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. In the seventeenth Fe site, Fe(17) is bonded to one Er(1), one Er(2), one Fe(1), one Fe(10), one Fe(13), one Fe(14), one Fe(2), one Fe(3), one Fe(4), one Fe(7), one Fe(8), and one Fe(9) atom to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(14)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(7)Er3Fe9 cuboctahedra,  a cornercorner with one Fe(8)Er3Fe9 cuboctahedra, corners with two equivalent Fe(18)Er2Fe10 cuboctahedra, corners with three equivalent Fe(6)Er3Fe9 cuboctahedra,  a cornercorner with one C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, and faces with two equivalent C(1)Er2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. In the eighteenth Fe site, Fe(18) is bonded to one Er(1), one Er(2), one Fe(1), one Fe(10), one Fe(11), one Fe(12), one Fe(2), one Fe(3), one Fe(4), one Fe(5), one Fe(6), and one Fe(9) atom to form distorted FeEr2Fe10 cuboctahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with three equivalent Fe(7)Er3Fe9 cuboctahedra, corners with three equivalent Fe(8)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(6)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(7)Er3Fe9 cuboctahedra,  an edgeedge with one Fe(8)Er3Fe9 cuboctahedra,  a faceface with one Fe(15)Er2Fe10 cuboctahedra,  a faceface with one Fe(16)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(14)Er2Fe10 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra,  a faceface with one C(2)Er2Fe4 octahedra, and faces with two equivalent C(1)Er2Fe4 octahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded to one Er(1), one Er(2), one Fe(10), one Fe(3), one Fe(4), and one Fe(9) atom to form CEr2Fe4 octahedra that share  a cornercorner with one Fe(15)Er2Fe10 cuboctahedra,  a cornercorner with one Fe(16)Er2Fe10 cuboctahedra, corners with two equivalent Fe(14)Er2Fe10 cuboctahedra, corners with two equivalent Fe(6)Er3Fe9 cuboctahedra, corners with two equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent Fe(8)Er3Fe9 cuboctahedra,  a cornercorner with one C(2)Er2Fe4 octahedra,  an edgeedge with one Fe(14)Er2Fe10 cuboctahedra,  a faceface with one Fe(6)Er3Fe9 cuboctahedra,  a faceface with one Fe(7)Er3Fe9 cuboctahedra,  a faceface with one Fe(8)Er3Fe9 cuboctahedra, faces with two equivalent Fe(17)Er2Fe10 cuboctahedra, and faces with two equivalent Fe(18)Er2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. In the second C site, C(2) is bonded to two equivalent Er(1), two equivalent Fe(11), and two equivalent Fe(5) atoms to form CEr2Fe4 octahedra that share corners with two equivalent Fe(17)Er2Fe10 cuboctahedra, corners with four equivalent Fe(7)Er3Fe9 cuboctahedra, corners with two equivalent C(1)Er2Fe4 octahedra, faces with two equivalent Fe(15)Er2Fe10 cuboctahedra, faces with two equivalent Fe(18)Er2Fe10 cuboctahedra, and faces with two equivalent Fe(7)Er3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 62°.