LaY is beta-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded to three equivalent La(3), six equivalent La(1), and three equivalent Y(2) atoms to form LaLa9Y3 cuboctahedra that share corners with three equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with three equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one Y(3)La6Y6 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. In the second La site, La(2) is bonded to six equivalent La(2), three equivalent Y(1), and three equivalent Y(3) atoms to form LaLa6Y6 cuboctahedra that share corners with three equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. In the third La site, La(3) is bonded to three equivalent La(1), six equivalent La(3), and three equivalent Y(3) atoms to form LaLa9Y3 cuboctahedra that share corners with three equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. In the fourth La site, La(2) is bonded to six equivalent La(2), three equivalent Y(1), and three equivalent Y(3) atoms to form LaLa6Y6 cuboctahedra that share corners with three equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. There are five inequivalent Y sites. In the first Y site, Y(1) is bonded to three equivalent La(2), three equivalent Y(2), and six equivalent Y(1) atoms to form YLa3Y9 cuboctahedra that share corners with three equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with three equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one Y(3)La6Y6 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. In the second Y site, Y(2) is bonded to three equivalent La(1), three equivalent Y(1), and six equivalent Y(2) atoms to form YLa3Y9 cuboctahedra that share corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one La(2)La6Y6 cuboctahedra,  a faceface with one La(3)La9Y3 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. In the third Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. In the fourth Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. In the fifth Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra.
LaY is beta-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent La sites. In the first La site, La(1) is bonded to three equivalent La(3), six equivalent La(1), and three equivalent Y(2) atoms to form LaLa9Y3 cuboctahedra that share corners with three equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with three equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one Y(3)La6Y6 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. All La(1)-La(3) bond lengths are 3.77 Å. All La(1)-La(1) bond lengths are 3.68 Å. All La(1)-Y(2) bond lengths are 3.70 Å. In the second La site, La(2) is bonded to six equivalent La(2), three equivalent Y(1), and three equivalent Y(3) atoms to form LaLa6Y6 cuboctahedra that share corners with three equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All La(2)-La(2) bond lengths are 3.68 Å. All La(2)-Y(1) bond lengths are 3.73 Å. All La(2)-Y(3) bond lengths are 3.67 Å. In the third La site, La(3) is bonded to three equivalent La(1), six equivalent La(3), and three equivalent Y(3) atoms to form LaLa9Y3 cuboctahedra that share corners with three equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All La(3)-La(3) bond lengths are 3.68 Å. All La(3)-Y(3) bond lengths are 3.65 Å. In the fourth La site, La(2) is bonded to six equivalent La(2), three equivalent Y(1), and three equivalent Y(3) atoms to form LaLa6Y6 cuboctahedra that share corners with three equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with three equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one Y(2)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All La(2)-La(2) bond lengths are 3.68 Å. All La(2)-Y(1) bond lengths are 3.73 Å. All La(2)-Y(3) bond lengths are 3.67 Å. There are five inequivalent Y sites. In the first Y site, Y(1) is bonded to three equivalent La(2), three equivalent Y(2), and six equivalent Y(1) atoms to form YLa3Y9 cuboctahedra that share corners with three equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with three equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one Y(3)La6Y6 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. All Y(1)-Y(2) bond lengths are 3.56 Å. All Y(1)-Y(1) bond lengths are 3.68 Å. In the second Y site, Y(2) is bonded to three equivalent La(1), three equivalent Y(1), and six equivalent Y(2) atoms to form YLa3Y9 cuboctahedra that share corners with six equivalent La(2)La6Y6 cuboctahedra, corners with six equivalent La(3)La9Y3 cuboctahedra, corners with six equivalent Y(2)La3Y9 cuboctahedra, edges with six equivalent La(1)La9Y3 cuboctahedra, edges with six equivalent Y(1)La3Y9 cuboctahedra, edges with six equivalent Y(2)La3Y9 cuboctahedra,  a faceface with one La(2)La6Y6 cuboctahedra,  a faceface with one La(3)La9Y3 cuboctahedra, faces with six equivalent La(1)La9Y3 cuboctahedra, faces with six equivalent Y(1)La3Y9 cuboctahedra, and faces with six equivalent Y(2)La3Y9 cuboctahedra. All Y(2)-Y(2) bond lengths are 3.68 Å. In the third Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All Y(3)-Y(3) bond lengths are 3.68 Å. In the fourth Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All Y(3)-La(3) bond lengths are 3.65 Å. All Y(3)-Y(3) bond lengths are 3.68 Å. In the fifth Y site, Y(3) is bonded to three equivalent La(2), three equivalent La(3), and six equivalent Y(3) atoms to form YLa6Y6 cuboctahedra that share corners with six equivalent La(1)La9Y3 cuboctahedra, corners with six equivalent Y(1)La3Y9 cuboctahedra, corners with six equivalent Y(3)La6Y6 cuboctahedra, edges with six equivalent La(2)La6Y6 cuboctahedra, edges with six equivalent La(3)La9Y3 cuboctahedra, edges with six equivalent Y(3)La6Y6 cuboctahedra,  a faceface with one La(1)La9Y3 cuboctahedra,  a faceface with one Y(1)La3Y9 cuboctahedra, faces with six equivalent La(2)La6Y6 cuboctahedra, faces with six equivalent La(3)La9Y3 cuboctahedra, and faces with six equivalent Y(3)La6Y6 cuboctahedra. All Y(3)-La(2) bond lengths are 3.67 Å. All Y(3)-La(3) bond lengths are 3.65 Å. All Y(3)-Y(3) bond lengths are 3.68 Å.