BeYCu4 crystallizes in the hexagonal P-6m2 space group. Be(1) is bonded in a 6-coordinate geometry to three equivalent Y(1), three equivalent Cu(1), and six equivalent Cu(2) atoms. Y(1) is bonded in a 18-coordinate geometry to three equivalent Be(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Be(1), three equivalent Y(1), and six equivalent Cu(2) atoms to form distorted CuY3Be3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Y4Be2Cu6 cuboctahedra, edges with six equivalent Cu(1)Y3Be3Cu6 cuboctahedra, faces with two equivalent Cu(1)Y3Be3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Y4Be2Cu6 cuboctahedra. In the second Cu site, Cu(2) is bonded to two equivalent Be(1), four equivalent Y(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form distorted CuY4Be2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Y3Be3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Y4Be2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Y4Be2Cu6 cuboctahedra, faces with six equivalent Cu(1)Y3Be3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Y4Be2Cu6 cuboctahedra.
BeYCu4 crystallizes in the hexagonal P-6m2 space group. Be(1) is bonded in a 6-coordinate geometry to three equivalent Y(1), three equivalent Cu(1), and six equivalent Cu(2) atoms. All Be(1)-Y(1) bond lengths are 2.92 Å. All Be(1)-Cu(1) bond lengths are 2.92 Å. All Be(1)-Cu(2) bond lengths are 2.40 Å. Y(1) is bonded in a 18-coordinate geometry to three equivalent Be(1), three equivalent Cu(1), and twelve equivalent Cu(2) atoms. All Y(1)-Cu(1) bond lengths are 2.92 Å. All Y(1)-Cu(2) bond lengths are 3.19 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to three equivalent Be(1), three equivalent Y(1), and six equivalent Cu(2) atoms to form distorted CuY3Be3Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Y4Be2Cu6 cuboctahedra, edges with six equivalent Cu(1)Y3Be3Cu6 cuboctahedra, faces with two equivalent Cu(1)Y3Be3Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Y4Be2Cu6 cuboctahedra. All Cu(1)-Cu(2) bond lengths are 2.45 Å. In the second Cu site, Cu(2) is bonded to two equivalent Be(1), four equivalent Y(1), two equivalent Cu(1), and four equivalent Cu(2) atoms to form distorted CuY4Be2Cu6 cuboctahedra that share corners with four equivalent Cu(1)Y3Be3Cu6 cuboctahedra, corners with sixteen equivalent Cu(2)Y4Be2Cu6 cuboctahedra, edges with ten equivalent Cu(2)Y4Be2Cu6 cuboctahedra, faces with six equivalent Cu(1)Y3Be3Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Y4Be2Cu6 cuboctahedra. There are two shorter (2.46 Å) and two longer (2.60 Å) Cu(2)-Cu(2) bond lengths.