Er10Mn13C18 crystallizes in the cubic I-43m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to four equivalent C(1) and four equivalent C(2) atoms. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one Mn(1) and six equivalent C(1) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 16-coordinate geometry to four equivalent Er(2) and twelve equivalent Mn(2) atoms. In the second Mn site, Mn(2) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one C(2), and two equivalent C(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Er(1), two equivalent Er(2), and two equivalent Mn(2) atoms to form a mixture of distorted corner and edge-sharing CEr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-69°. In the second C site, C(2) is bonded in a 7-coordinate geometry to four equivalent Er(1), two equivalent Mn(2), and one C(2) atom.
Er10Mn13C18 crystallizes in the cubic I-43m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to four equivalent C(1) and four equivalent C(2) atoms. All Er(1)-C(1) bond lengths are 2.45 Å. All Er(1)-C(2) bond lengths are 2.60 Å. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one Mn(1) and six equivalent C(1) atoms. The Er(2)-Mn(1) bond length is 3.55 Å. There are three shorter (2.55 Å) and three longer (2.62 Å) Er(2)-C(1) bond lengths. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 16-coordinate geometry to four equivalent Er(2) and twelve equivalent Mn(2) atoms. All Mn(1)-Mn(2) bond lengths are 2.80 Å. In the second Mn site, Mn(2) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one C(2), and two equivalent C(1) atoms. The Mn(2)-C(2) bond length is 2.05 Å. Both Mn(2)-C(1) bond lengths are 1.86 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Er(1), two equivalent Er(2), and two equivalent Mn(2) atoms to form a mixture of distorted corner and edge-sharing CEr4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 4-69°. In the second C site, C(2) is bonded in a 7-coordinate geometry to four equivalent Er(1), two equivalent Mn(2), and one C(2) atom. The C(2)-C(2) bond length is 1.38 Å.