ReB4 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Re sites. In the first Re site, Re(1) is bonded in a 14-coordinate geometry to two equivalent B(2) and twelve equivalent B(1) atoms. In the second Re site, Re(2) is bonded to twelve equivalent B(1) atoms to form face-sharing ReB12 cuboctahedra. There are two inequivalent B sites. In the first B site, B(2) is bonded in a 8-coordinate geometry to one Re(1), one B(2), and six equivalent B(1) atoms. In the second B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Re(1), two equivalent Re(2), two equivalent B(2), and three equivalent B(1) atoms.
ReB4 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Re sites. In the first Re site, Re(1) is bonded in a 14-coordinate geometry to two equivalent B(2) and twelve equivalent B(1) atoms. Both Re(1)-B(2) bond lengths are 2.25 Å. All Re(1)-B(1) bond lengths are 2.38 Å. In the second Re site, Re(2) is bonded to twelve equivalent B(1) atoms to form face-sharing ReB12 cuboctahedra. All Re(2)-B(1) bond lengths are 2.40 Å. There are two inequivalent B sites. In the first B site, B(2) is bonded in a 8-coordinate geometry to one Re(1), one B(2), and six equivalent B(1) atoms. The B(2)-B(2) bond length is 1.69 Å. All B(2)-B(1) bond lengths are 1.94 Å. In the second B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Re(1), two equivalent Re(2), two equivalent B(2), and three equivalent B(1) atoms. There is one shorter (1.77 Å) and two longer (1.84 Å) B(1)-B(1) bond lengths.