HoNiB4 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 20-coordinate geometry to four equivalent Ni(1), eight equivalent B(1), and eight equivalent B(2) atoms. In the second Ho site, Ho(2) is bonded in a 20-coordinate geometry to four equivalent Ni(1), eight equivalent B(1), and eight equivalent B(2) atoms. Ni(1) is bonded in a 6-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent B(1), and four equivalent B(2) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), one Ni(1), two equivalent B(1), and two equivalent B(2) atoms. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent Ni(1), one B(2), and two equivalent B(1) atoms.
HoNiB4 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 20-coordinate geometry to four equivalent Ni(1), eight equivalent B(1), and eight equivalent B(2) atoms. All Ho(1)-Ni(1) bond lengths are 3.03 Å. All Ho(1)-B(1) bond lengths are 2.82 Å. There are four shorter (2.75 Å) and four longer (2.86 Å) Ho(1)-B(2) bond lengths. In the second Ho site, Ho(2) is bonded in a 20-coordinate geometry to four equivalent Ni(1), eight equivalent B(1), and eight equivalent B(2) atoms. All Ho(2)-Ni(1) bond lengths are 2.94 Å. All Ho(2)-B(1) bond lengths are 2.83 Å. All Ho(2)-B(2) bond lengths are 2.78 Å. Ni(1) is bonded in a 6-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent B(1), and four equivalent B(2) atoms. Both Ni(1)-B(1) bond lengths are 2.06 Å. All Ni(1)-B(2) bond lengths are 2.17 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), one Ni(1), two equivalent B(1), and two equivalent B(2) atoms. There is one shorter (1.67 Å) and one longer (1.74 Å) B(1)-B(1) bond length. Both B(1)-B(2) bond lengths are 1.74 Å. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Ho(1), two equivalent Ho(2), two equivalent Ni(1), one B(2), and two equivalent B(1) atoms. The B(2)-B(2) bond length is 1.69 Å.