Be4TaMo crystallizes in the trigonal P-3m1 space group. There are three inequivalent Be sites. In the first Be site, Be(1) is bonded to six equivalent Be(3) and six equivalent Mo(1) atoms to form BeBe6Mo6 cuboctahedra that share corners with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(1)Be6Mo6 cuboctahedra, faces with two equivalent Be(2)Ta6Be6 cuboctahedra, and faces with eighteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra. In the second Be site, Be(2) is bonded to six equivalent Be(3) and six equivalent Ta(1) atoms to form BeTa6Be6 cuboctahedra that share corners with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(2)Ta6Be6 cuboctahedra, faces with two equivalent Be(1)Be6Mo6 cuboctahedra, and faces with eighteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra. In the third Be site, Be(3) is bonded to one Be(1), one Be(2), four equivalent Be(3), three equivalent Ta(1), and three equivalent Mo(1) atoms to form BeTa3Be6Mo3 cuboctahedra that share corners with two equivalent Be(1)Be6Mo6 cuboctahedra, corners with two equivalent Be(2)Ta6Be6 cuboctahedra, corners with fourteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(3)Ta3Be6Mo3 cuboctahedra, faces with three equivalent Be(1)Be6Mo6 cuboctahedra, faces with three equivalent Be(2)Ta6Be6 cuboctahedra, and faces with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra. Ta(1) is bonded in a 16-coordinate geometry to three equivalent Be(2), nine equivalent Be(3), three equivalent Ta(1), and one Mo(1) atom. Mo(1) is bonded in a 13-coordinate geometry to three equivalent Be(1), nine equivalent Be(3), and one Ta(1) atom.
Be4TaMo crystallizes in the trigonal P-3m1 space group. There are three inequivalent Be sites. In the first Be site, Be(1) is bonded to six equivalent Be(3) and six equivalent Mo(1) atoms to form BeBe6Mo6 cuboctahedra that share corners with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(1)Be6Mo6 cuboctahedra, faces with two equivalent Be(2)Ta6Be6 cuboctahedra, and faces with eighteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra. All Be(1)-Be(3) bond lengths are 2.26 Å. All Be(1)-Mo(1) bond lengths are 2.66 Å. In the second Be site, Be(2) is bonded to six equivalent Be(3) and six equivalent Ta(1) atoms to form BeTa6Be6 cuboctahedra that share corners with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(2)Ta6Be6 cuboctahedra, faces with two equivalent Be(1)Be6Mo6 cuboctahedra, and faces with eighteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra. All Be(2)-Be(3) bond lengths are 2.30 Å. All Be(2)-Ta(1) bond lengths are 2.67 Å. In the third Be site, Be(3) is bonded to one Be(1), one Be(2), four equivalent Be(3), three equivalent Ta(1), and three equivalent Mo(1) atoms to form BeTa3Be6Mo3 cuboctahedra that share corners with two equivalent Be(1)Be6Mo6 cuboctahedra, corners with two equivalent Be(2)Ta6Be6 cuboctahedra, corners with fourteen equivalent Be(3)Ta3Be6Mo3 cuboctahedra, edges with six equivalent Be(3)Ta3Be6Mo3 cuboctahedra, faces with three equivalent Be(1)Be6Mo6 cuboctahedra, faces with three equivalent Be(2)Ta6Be6 cuboctahedra, and faces with twelve equivalent Be(3)Ta3Be6Mo3 cuboctahedra. There are two shorter (2.21 Å) and two longer (2.33 Å) Be(3)-Be(3) bond lengths. There are two shorter (2.64 Å) and one longer (2.71 Å) Be(3)-Ta(1) bond length. There is one shorter (2.60 Å) and two longer (2.65 Å) Be(3)-Mo(1) bond lengths. Ta(1) is bonded in a 16-coordinate geometry to three equivalent Be(2), nine equivalent Be(3), three equivalent Ta(1), and one Mo(1) atom. All Ta(1)-Ta(1) bond lengths are 2.82 Å. The Ta(1)-Mo(1) bond length is 2.73 Å. Mo(1) is bonded in a 13-coordinate geometry to three equivalent Be(1), nine equivalent Be(3), and one Ta(1) atom.