Er2Cr2C3 crystallizes in the monoclinic C2/m space group. Er(1) is bonded in a 5-coordinate geometry to two equivalent C(1) and three equivalent C(2) atoms. Cr(1) is bonded to one C(1) and three equivalent C(2) atoms to form a mixture of corner and edge-sharing CrC4 trigonal pyramids. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Er(1) and two equivalent Cr(1) atoms to form edge-sharing CEr4Cr2 octahedra. In the second C site, C(2) is bonded in a 6-coordinate geometry to three equivalent Er(1) and three equivalent Cr(1) atoms.
Er2Cr2C3 crystallizes in the monoclinic C2/m space group. Er(1) is bonded in a 5-coordinate geometry to two equivalent C(1) and three equivalent C(2) atoms. Both Er(1)-C(1) bond lengths are 2.44 Å. There is one shorter (2.42 Å) and two longer (2.60 Å) Er(1)-C(2) bond lengths. Cr(1) is bonded to one C(1) and three equivalent C(2) atoms to form a mixture of corner and edge-sharing CrC4 trigonal pyramids. The Cr(1)-C(1) bond length is 1.88 Å. There are two shorter (1.96 Å) and one longer (1.98 Å) Cr(1)-C(2) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded to four equivalent Er(1) and two equivalent Cr(1) atoms to form edge-sharing CEr4Cr2 octahedra. In the second C site, C(2) is bonded in a 6-coordinate geometry to three equivalent Er(1) and three equivalent Cr(1) atoms.