Be4B crystallizes in the tetragonal P4/nmm space group. There are three inequivalent Be sites. In the first Be site, Be(1) is bonded to four equivalent B(1) atoms to form a mixture of distorted edge and corner-sharing BeB4 tetrahedra. In the second Be site, Be(2) is bonded in a 13-coordinate geometry to four equivalent Be(2), eight equivalent Be(3), and one B(1) atom. In the third Be site, Be(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Be(2) and two equivalent B(1) atoms. B(1) is bonded in a 9-coordinate geometry to one Be(2), four equivalent Be(1), and four equivalent Be(3) atoms.
Be4B crystallizes in the tetragonal P4/nmm space group. There are three inequivalent Be sites. In the first Be site, Be(1) is bonded to four equivalent B(1) atoms to form a mixture of distorted edge and corner-sharing BeB4 tetrahedra. All Be(1)-B(1) bond lengths are 2.06 Å. In the second Be site, Be(2) is bonded in a 13-coordinate geometry to four equivalent Be(2), eight equivalent Be(3), and one B(1) atom. All Be(2)-Be(2) bond lengths are 2.39 Å. There are four shorter (2.08 Å) and four longer (2.25 Å) Be(2)-Be(3) bond lengths. The Be(2)-B(1) bond length is 2.18 Å. In the third Be site, Be(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Be(2) and two equivalent B(1) atoms. Both Be(3)-B(1) bond lengths are 1.93 Å. B(1) is bonded in a 9-coordinate geometry to one Be(2), four equivalent Be(1), and four equivalent Be(3) atoms.