ErRuFe crystallizes in the orthorhombic Imma space group. Er(1) is bonded in a 12-coordinate geometry to six equivalent Ru(1) and six equivalent Fe(1) atoms. Ru(1) is bonded to six equivalent Er(1), two equivalent Ru(1), and four equivalent Fe(1) atoms to form distorted RuEr6Fe4Ru2 cuboctahedra that share corners with eight equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, corners with ten equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, edges with six equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, faces with six equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, and faces with twelve equivalent Fe(1)Er6Fe2Ru4 cuboctahedra. Fe(1) is bonded to six equivalent Er(1), four equivalent Ru(1), and two equivalent Fe(1) atoms to form FeEr6Fe2Ru4 cuboctahedra that share corners with eight equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, corners with ten equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, edges with six equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, faces with six equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, and faces with twelve equivalent Ru(1)Er6Fe4Ru2 cuboctahedra.
ErRuFe crystallizes in the orthorhombic Imma space group. Er(1) is bonded in a 12-coordinate geometry to six equivalent Ru(1) and six equivalent Fe(1) atoms. There are four shorter (3.04 Å) and two longer (3.05 Å) Er(1)-Ru(1) bond lengths. There are two shorter (3.04 Å) and four longer (3.11 Å) Er(1)-Fe(1) bond lengths. Ru(1) is bonded to six equivalent Er(1), two equivalent Ru(1), and four equivalent Fe(1) atoms to form distorted RuEr6Fe4Ru2 cuboctahedra that share corners with eight equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, corners with ten equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, edges with six equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, faces with six equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, and faces with twelve equivalent Fe(1)Er6Fe2Ru4 cuboctahedra. Both Ru(1)-Ru(1) bond lengths are 2.68 Å. All Ru(1)-Fe(1) bond lengths are 2.61 Å. Fe(1) is bonded to six equivalent Er(1), four equivalent Ru(1), and two equivalent Fe(1) atoms to form FeEr6Fe2Ru4 cuboctahedra that share corners with eight equivalent Ru(1)Er6Fe4Ru2 cuboctahedra, corners with ten equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, edges with six equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, faces with six equivalent Fe(1)Er6Fe2Ru4 cuboctahedra, and faces with twelve equivalent Ru(1)Er6Fe4Ru2 cuboctahedra. Both Fe(1)-Fe(1) bond lengths are 2.57 Å.