Er is alpha Samarium structured and crystallizes in the trigonal R-3m space group. There are five inequivalent Er sites. In the first Er site, Er(1) is bonded to six equivalent Er(1) and six Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. In the second Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. In the third Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. In the fourth Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. In the fifth Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra.
Er is alpha Samarium structured and crystallizes in the trigonal R-3m space group. There are five inequivalent Er sites. In the first Er site, Er(1) is bonded to six equivalent Er(1) and six Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. All Er(1)-Er(1) bond lengths are 3.55 Å. All Er(1)-Er(2,2) bond lengths are 3.50 Å. In the second Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. All Er(2)-Er(1) bond lengths are 3.50 Å. There are three shorter (3.49 Å) and six longer (3.55 Å) Er(2)-Er(2,2) bond lengths. In the third Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. All Er(2)-Er(2) bond lengths are 3.55 Å. In the fourth Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. There are three shorter (3.49 Å) and six longer (3.55 Å) Er(2)-Er(2,2) bond lengths. In the fifth Er site, Er(2) is bonded to three equivalent Er(1) and nine Er(2,2) atoms to form a mixture of face, corner, and edge-sharing ErEr12 cuboctahedra. All Er(2)-Er(1) bond lengths are 3.50 Å. All Er(2)-Er(2) bond lengths are 3.55 Å.