Er2ReC2 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent C(1) and two equivalent C(2) atoms. In the second Er site, Er(2) is bonded to two equivalent C(2) and three equivalent C(1) atoms to form a mixture of corner and edge-sharing ErC5 square pyramids. Re(1) is bonded in a 3-coordinate geometry to one C(1) and two equivalent C(2) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Er(1), three equivalent Er(2), and one Re(1) atom to form CEr5Re octahedra that share corners with two equivalent C(2)Er4Re2 octahedra, corners with four equivalent C(1)Er5Re octahedra, edges with two equivalent C(1)Er5Re octahedra, and edges with five equivalent C(2)Er4Re2 octahedra. The corner-sharing octahedral tilt angles range from 3-38°. In the second C site, C(2) is bonded to two equivalent Er(1), two equivalent Er(2), and two equivalent Re(1) atoms to form CEr4Re2 octahedra that share corners with two equivalent C(2)Er4Re2 octahedra, corners with two equivalent C(1)Er5Re octahedra, edges with two equivalent C(2)Er4Re2 octahedra, and edges with five equivalent C(1)Er5Re octahedra. The corner-sharing octahedral tilt angles range from 12-38°.
Er2ReC2 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent C(1) and two equivalent C(2) atoms. There is one shorter (2.48 Å) and one longer (2.66 Å) Er(1)-C(1) bond length. Both Er(1)-C(2) bond lengths are 2.53 Å. In the second Er site, Er(2) is bonded to two equivalent C(2) and three equivalent C(1) atoms to form a mixture of corner and edge-sharing ErC5 square pyramids. There is one shorter (2.46 Å) and one longer (2.52 Å) Er(2)-C(2) bond length. There are two shorter (2.52 Å) and one longer (2.53 Å) Er(2)-C(1) bond length. Re(1) is bonded in a 3-coordinate geometry to one C(1) and two equivalent C(2) atoms. The Re(1)-C(1) bond length is 1.92 Å. There is one shorter (1.95 Å) and one longer (2.04 Å) Re(1)-C(2) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded to two equivalent Er(1), three equivalent Er(2), and one Re(1) atom to form CEr5Re octahedra that share corners with two equivalent C(2)Er4Re2 octahedra, corners with four equivalent C(1)Er5Re octahedra, edges with two equivalent C(1)Er5Re octahedra, and edges with five equivalent C(2)Er4Re2 octahedra. The corner-sharing octahedral tilt angles range from 3-38°. In the second C site, C(2) is bonded to two equivalent Er(1), two equivalent Er(2), and two equivalent Re(1) atoms to form CEr4Re2 octahedra that share corners with two equivalent C(2)Er4Re2 octahedra, corners with two equivalent C(1)Er5Re octahedra, edges with two equivalent C(2)Er4Re2 octahedra, and edges with five equivalent C(1)Er5Re octahedra. The corner-sharing octahedral tilt angles range from 12-38°.