EuLa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Eu(1) is bonded to four equivalent La(2) and eight equivalent La(1) atoms to form EuLa12 cuboctahedra that share corners with four equivalent Eu(1)La12 cuboctahedra, corners with eight equivalent La(2)La8Eu4 cuboctahedra, edges with eight equivalent Eu(1)La12 cuboctahedra, edges with sixteen equivalent La(1)La8Eu4 cuboctahedra, faces with four equivalent Eu(1)La12 cuboctahedra, faces with six equivalent La(2)La8Eu4 cuboctahedra, and faces with eight equivalent La(1)La8Eu4 cuboctahedra. There are two inequivalent La sites. In the first La site, La(1) is bonded to four equivalent Eu(1), four equivalent La(1), and four equivalent La(2) atoms to form LaLa8Eu4 cuboctahedra that share corners with twelve equivalent La(1)La8Eu4 cuboctahedra, edges with eight equivalent Eu(1)La12 cuboctahedra, edges with eight equivalent La(1)La8Eu4 cuboctahedra, edges with eight equivalent La(2)La8Eu4 cuboctahedra, faces with four equivalent Eu(1)La12 cuboctahedra, faces with four equivalent La(2)La8Eu4 cuboctahedra, and faces with ten equivalent La(1)La8Eu4 cuboctahedra. In the second La site, La(2) is bonded to four equivalent Eu(1) and eight equivalent La(1) atoms to form LaLa8Eu4 cuboctahedra that share corners with four equivalent La(2)La8Eu4 cuboctahedra, corners with eight equivalent Eu(1)La12 cuboctahedra, edges with eight equivalent La(2)La8Eu4 cuboctahedra, edges with sixteen equivalent La(1)La8Eu4 cuboctahedra, faces with four equivalent La(2)La8Eu4 cuboctahedra, faces with six equivalent Eu(1)La12 cuboctahedra, and faces with eight equivalent La(1)La8Eu4 cuboctahedra.
EuLa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Eu(1) is bonded to four equivalent La(2) and eight equivalent La(1) atoms to form EuLa12 cuboctahedra that share corners with four equivalent Eu(1)La12 cuboctahedra, corners with eight equivalent La(2)La8Eu4 cuboctahedra, edges with eight equivalent Eu(1)La12 cuboctahedra, edges with sixteen equivalent La(1)La8Eu4 cuboctahedra, faces with four equivalent Eu(1)La12 cuboctahedra, faces with six equivalent La(2)La8Eu4 cuboctahedra, and faces with eight equivalent La(1)La8Eu4 cuboctahedra. All Eu(1)-La(2) bond lengths are 3.76 Å. All Eu(1)-La(1) bond lengths are 3.78 Å. There are two inequivalent La sites. In the first La site, La(1) is bonded to four equivalent Eu(1), four equivalent La(1), and four equivalent La(2) atoms to form LaLa8Eu4 cuboctahedra that share corners with twelve equivalent La(1)La8Eu4 cuboctahedra, edges with eight equivalent Eu(1)La12 cuboctahedra, edges with eight equivalent La(1)La8Eu4 cuboctahedra, edges with eight equivalent La(2)La8Eu4 cuboctahedra, faces with four equivalent Eu(1)La12 cuboctahedra, faces with four equivalent La(2)La8Eu4 cuboctahedra, and faces with ten equivalent La(1)La8Eu4 cuboctahedra. All La(1)-La(1) bond lengths are 3.76 Å. All La(1)-La(2) bond lengths are 3.78 Å. In the second La site, La(2) is bonded to four equivalent Eu(1) and eight equivalent La(1) atoms to form LaLa8Eu4 cuboctahedra that share corners with four equivalent La(2)La8Eu4 cuboctahedra, corners with eight equivalent Eu(1)La12 cuboctahedra, edges with eight equivalent La(2)La8Eu4 cuboctahedra, edges with sixteen equivalent La(1)La8Eu4 cuboctahedra, faces with four equivalent La(2)La8Eu4 cuboctahedra, faces with six equivalent Eu(1)La12 cuboctahedra, and faces with eight equivalent La(1)La8Eu4 cuboctahedra.