HfNiGa2 crystallizes in the tetragonal I4mm space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 12-coordinate geometry to four equivalent Ni(3), four equivalent Ga(1), and four equivalent Ga(3) atoms. In the second Hf site, Hf(2) is bonded in a 12-coordinate geometry to four equivalent Ni(1), four equivalent Ga(1), and four equivalent Ga(3) atoms. In the third Hf site, Hf(3) is bonded in a 10-coordinate geometry to two equivalent Ni(1), two equivalent Ni(3), two equivalent Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. In the fourth Hf site, Hf(4) is bonded in a 13-coordinate geometry to one Ni(2), one Ni(3), two equivalent Ni(1), one Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(3) is bonded in a 10-coordinate geometry to one Hf(1), one Hf(4), two equivalent Hf(3), one Ga(1), one Ga(2), two equivalent Ga(3), and two equivalent Ga(4) atoms. In the second Ni site, Ni(1) is bonded in a 10-coordinate geometry to one Hf(2), two equivalent Hf(3), two equivalent Hf(4), one Ga(3), two equivalent Ga(1), and two equivalent Ga(4) atoms. In the third Ni site, Ni(2) is bonded in a 8-coordinate geometry to two equivalent Hf(4), four equivalent Ga(2), and four equivalent Ga(4) atoms. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to one Hf(1), one Hf(2), one Hf(4), two equivalent Hf(3), one Ni(3), two equivalent Ni(1), one Ga(2), and two equivalent Ga(1) atoms. In the second Ga site, Ga(2) is bonded in a 13-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Ni(3), two equivalent Ni(2), one Ga(1), one Ga(2), and four equivalent Ga(4) atoms. In the third Ga site, Ga(3) is bonded in a 11-coordinate geometry to one Hf(1), one Hf(2), two equivalent Hf(3), two equivalent Hf(4), one Ni(1), two equivalent Ni(3), and two equivalent Ga(4) atoms. In the fourth Ga site, Ga(4) is bonded in a 10-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Ni(1), one Ni(2), one Ni(3), one Ga(3), and two equivalent Ga(2) atoms.
HfNiGa2 crystallizes in the tetragonal I4mm space group. There are four inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 12-coordinate geometry to four equivalent Ni(3), four equivalent Ga(1), and four equivalent Ga(3) atoms. All Hf(1)-Ni(3) bond lengths are 2.67 Å. All Hf(1)-Ga(1) bond lengths are 3.04 Å. All Hf(1)-Ga(3) bond lengths are 2.92 Å. In the second Hf site, Hf(2) is bonded in a 12-coordinate geometry to four equivalent Ni(1), four equivalent Ga(1), and four equivalent Ga(3) atoms. All Hf(2)-Ni(1) bond lengths are 2.92 Å. All Hf(2)-Ga(1) bond lengths are 2.94 Å. All Hf(2)-Ga(3) bond lengths are 2.92 Å. In the third Hf site, Hf(3) is bonded in a 10-coordinate geometry to two equivalent Ni(1), two equivalent Ni(3), two equivalent Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. There is one shorter (2.68 Å) and one longer (2.83 Å) Hf(3)-Ni(1) bond length. Both Hf(3)-Ni(3) bond lengths are 2.79 Å. Both Hf(3)-Ga(1) bond lengths are 2.87 Å. Both Hf(3)-Ga(2) bond lengths are 3.34 Å. There is one shorter (3.08 Å) and one longer (3.12 Å) Hf(3)-Ga(3) bond length. There are two shorter (2.84 Å) and two longer (2.85 Å) Hf(3)-Ga(4) bond lengths. In the fourth Hf site, Hf(4) is bonded in a 13-coordinate geometry to one Ni(2), one Ni(3), two equivalent Ni(1), one Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. The Hf(4)-Ni(2) bond length is 3.21 Å. The Hf(4)-Ni(3) bond length is 3.02 Å. Both Hf(4)-Ni(1) bond lengths are 2.81 Å. The Hf(4)-Ga(1) bond length is 3.12 Å. Both Hf(4)-Ga(2) bond lengths are 3.00 Å. Both Hf(4)-Ga(3) bond lengths are 2.81 Å. All Hf(4)-Ga(4) bond lengths are 2.83 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(3) is bonded in a 10-coordinate geometry to one Hf(1), one Hf(4), two equivalent Hf(3), one Ga(1), one Ga(2), two equivalent Ga(3), and two equivalent Ga(4) atoms. The Ni(3)-Ga(1) bond length is 2.61 Å. The Ni(3)-Ga(2) bond length is 2.44 Å. Both Ni(3)-Ga(3) bond lengths are 2.51 Å. Both Ni(3)-Ga(4) bond lengths are 2.55 Å. In the second Ni site, Ni(1) is bonded in a 10-coordinate geometry to one Hf(2), two equivalent Hf(3), two equivalent Hf(4), one Ga(3), two equivalent Ga(1), and two equivalent Ga(4) atoms. The Ni(1)-Ga(3) bond length is 2.59 Å. Both Ni(1)-Ga(1) bond lengths are 2.47 Å. Both Ni(1)-Ga(4) bond lengths are 2.52 Å. In the third Ni site, Ni(2) is bonded in a 8-coordinate geometry to two equivalent Hf(4), four equivalent Ga(2), and four equivalent Ga(4) atoms. There are two shorter (2.47 Å) and two longer (2.51 Å) Ni(2)-Ga(2) bond lengths. All Ni(2)-Ga(4) bond lengths are 2.53 Å. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to one Hf(1), one Hf(2), one Hf(4), two equivalent Hf(3), one Ni(3), two equivalent Ni(1), one Ga(2), and two equivalent Ga(1) atoms. The Ga(1)-Ga(2) bond length is 3.00 Å. Both Ga(1)-Ga(1) bond lengths are 2.77 Å. In the second Ga site, Ga(2) is bonded in a 13-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Ni(3), two equivalent Ni(2), one Ga(1), one Ga(2), and four equivalent Ga(4) atoms. The Ga(2)-Ga(2) bond length is 2.89 Å. There are two shorter (2.66 Å) and two longer (2.79 Å) Ga(2)-Ga(4) bond lengths. In the third Ga site, Ga(3) is bonded in a 11-coordinate geometry to one Hf(1), one Hf(2), two equivalent Hf(3), two equivalent Hf(4), one Ni(1), two equivalent Ni(3), and two equivalent Ga(4) atoms. Both Ga(3)-Ga(4) bond lengths are 2.81 Å. In the fourth Ga site, Ga(4) is bonded in a 10-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Ni(1), one Ni(2), one Ni(3), one Ga(3), and two equivalent Ga(2) atoms.