Er3In is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Er(1) is bonded to eight equivalent Er(1) and four equivalent In(1) atoms to form distorted ErEr8In4 cuboctahedra that share corners with four equivalent In(1)Er12 cuboctahedra, corners with fourteen equivalent Er(1)Er8In4 cuboctahedra, edges with six equivalent In(1)Er12 cuboctahedra, edges with twelve equivalent Er(1)Er8In4 cuboctahedra, faces with four equivalent In(1)Er12 cuboctahedra, and faces with sixteen equivalent Er(1)Er8In4 cuboctahedra. In(1) is bonded to twelve equivalent Er(1) atoms to form InEr12 cuboctahedra that share corners with six equivalent In(1)Er12 cuboctahedra, corners with twelve equivalent Er(1)Er8In4 cuboctahedra, edges with eighteen equivalent Er(1)Er8In4 cuboctahedra, faces with eight equivalent In(1)Er12 cuboctahedra, and faces with twelve equivalent Er(1)Er8In4 cuboctahedra.
Er3In is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Er(1) is bonded to eight equivalent Er(1) and four equivalent In(1) atoms to form distorted ErEr8In4 cuboctahedra that share corners with four equivalent In(1)Er12 cuboctahedra, corners with fourteen equivalent Er(1)Er8In4 cuboctahedra, edges with six equivalent In(1)Er12 cuboctahedra, edges with twelve equivalent Er(1)Er8In4 cuboctahedra, faces with four equivalent In(1)Er12 cuboctahedra, and faces with sixteen equivalent Er(1)Er8In4 cuboctahedra. There are a spread of Er(1)-Er(1) bond distances ranging from 3.30-3.46 Å. There are two shorter (3.37 Å) and two longer (3.38 Å) Er(1)-In(1) bond lengths. In(1) is bonded to twelve equivalent Er(1) atoms to form InEr12 cuboctahedra that share corners with six equivalent In(1)Er12 cuboctahedra, corners with twelve equivalent Er(1)Er8In4 cuboctahedra, edges with eighteen equivalent Er(1)Er8In4 cuboctahedra, faces with eight equivalent In(1)Er12 cuboctahedra, and faces with twelve equivalent Er(1)Er8In4 cuboctahedra.