ErRu2CP crystallizes in the orthorhombic Cmcm space group. Er(1) is bonded in a 4-coordinate geometry to four equivalent C(1) and three equivalent P(1) atoms. Ru(1) is bonded in a distorted single-bond geometry to one C(1) and three equivalent P(1) atoms. C(1) is bonded to four equivalent Er(1) and two equivalent Ru(1) atoms to form a mixture of corner and edge-sharing CEr4Ru2 octahedra. The corner-sharing octahedral tilt angles are 21°. P(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Ru(1) atoms.
ErRu2CP crystallizes in the orthorhombic Cmcm space group. Er(1) is bonded in a 4-coordinate geometry to four equivalent C(1) and three equivalent P(1) atoms. All Er(1)-C(1) bond lengths are 2.62 Å. There is one shorter (3.07 Å) and two longer (3.11 Å) Er(1)-P(1) bond lengths. Ru(1) is bonded in a distorted single-bond geometry to one C(1) and three equivalent P(1) atoms. The Ru(1)-C(1) bond length is 1.86 Å. There is one shorter (2.41 Å) and two longer (2.45 Å) Ru(1)-P(1) bond lengths. C(1) is bonded to four equivalent Er(1) and two equivalent Ru(1) atoms to form a mixture of corner and edge-sharing CEr4Ru2 octahedra. The corner-sharing octahedral tilt angles are 21°. P(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Ru(1) atoms.