HfCoGa2 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 Co(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 Co(1), four equivalent Ga(1), and four equivalent Ga(3) atoms. In the third Hf site, Hf(3) is bonded in a 14-coordinate geometry to two equivalent Co(1), two equivalent Co(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 8-coordinate geometry to one Co(3), two equivalent Co(1), one Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. There are three inequivalent Co sites. In the first Co site, Co(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 Co site, Co(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 Co site, Co(2) is bonded in a 8-coordinate geometry to 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 13-coordinate geometry to one Hf(1), one Hf(2), one Hf(4), two equivalent Hf(3), one Co(3), two equivalent Co(1), one Ga(2), two equivalent Ga(1), and two equivalent Ga(4) 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 Co(3), two equivalent Co(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 Co(1), two equivalent Co(3), and two equivalent Ga(4) atoms. In the fourth Ga site, Ga(4) is bonded in a 7-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Co(1), one Co(2), one Co(3), one Ga(1), one Ga(3), and two equivalent Ga(2) atoms.
HfCoGa2 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 Co(3), four equivalent Ga(1), and four equivalent Ga(3) atoms. All Hf(1)-Co(3) bond lengths are 2.63 Å. All Hf(1)-Ga(1) bond lengths are 2.99 Å. All Hf(1)-Ga(3) bond lengths are 2.90 Å. In the second Hf site, Hf(2) is bonded in a 12-coordinate geometry to four equivalent Co(1), four equivalent Ga(1), and four equivalent Ga(3) atoms. All Hf(2)-Co(1) bond lengths are 2.85 Å. All Hf(2)-Ga(1) bond lengths are 2.84 Å. All Hf(2)-Ga(3) bond lengths are 2.96 Å. In the third Hf site, Hf(3) is bonded in a 14-coordinate geometry to two equivalent Co(1), two equivalent Co(3), two equivalent Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. There is one shorter (2.65 Å) and one longer (2.86 Å) Hf(3)-Co(1) bond length. Both Hf(3)-Co(3) bond lengths are 2.72 Å. Both Hf(3)-Ga(1) bond lengths are 2.81 Å. Both Hf(3)-Ga(2) bond lengths are 3.29 Å. There is one shorter (3.01 Å) and one longer (3.14 Å) Hf(3)-Ga(3) bond length. There are two shorter (2.81 Å) and two longer (2.87 Å) Hf(3)-Ga(4) bond lengths. In the fourth Hf site, Hf(4) is bonded in a 8-coordinate geometry to one Co(3), two equivalent Co(1), one Ga(1), two equivalent Ga(2), two equivalent Ga(3), and four equivalent Ga(4) atoms. The Hf(4)-Co(3) bond length is 3.03 Å. Both Hf(4)-Co(1) bond lengths are 2.69 Å. The Hf(4)-Ga(1) bond length is 2.99 Å. Both Hf(4)-Ga(2) bond lengths are 3.02 Å. Both Hf(4)-Ga(3) bond lengths are 2.77 Å. There are two shorter (2.79 Å) and two longer (2.85 Å) Hf(4)-Ga(4) bond lengths. There are three inequivalent Co sites. In the first Co site, Co(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 Co(3)-Ga(1) bond length is 2.59 Å. The Co(3)-Ga(2) bond length is 2.41 Å. Both Co(3)-Ga(3) bond lengths are 2.46 Å. Both Co(3)-Ga(4) bond lengths are 2.50 Å. In the second Co site, Co(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 Co(1)-Ga(3) bond length is 2.56 Å. Both Co(1)-Ga(1) bond lengths are 2.46 Å. Both Co(1)-Ga(4) bond lengths are 2.51 Å. In the third Co site, Co(2) is bonded in a 8-coordinate geometry to four equivalent Ga(2) and four equivalent Ga(4) atoms. There are two shorter (2.45 Å) and two longer (2.46 Å) Co(2)-Ga(2) bond lengths. All Co(2)-Ga(4) bond lengths are 2.48 Å. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 13-coordinate geometry to one Hf(1), one Hf(2), one Hf(4), two equivalent Hf(3), one Co(3), two equivalent Co(1), one Ga(2), two equivalent Ga(1), and two equivalent Ga(4) atoms. The Ga(1)-Ga(2) bond length is 2.95 Å. Both Ga(1)-Ga(1) bond lengths are 2.78 Å. Both Ga(1)-Ga(4) bond lengths are 3.08 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 Co(3), two equivalent Co(2), one Ga(1), one Ga(2), and four equivalent Ga(4) atoms. The Ga(2)-Ga(2) bond length is 2.82 Å. There are two shorter (2.65 Å) and two longer (2.73 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 Co(1), two equivalent Co(3), and two equivalent Ga(4) atoms. Both Ga(3)-Ga(4) bond lengths are 2.78 Å. In the fourth Ga site, Ga(4) is bonded in a 7-coordinate geometry to two equivalent Hf(3), two equivalent Hf(4), one Co(1), one Co(2), one Co(3), one Ga(1), one Ga(3), and two equivalent Ga(2) atoms.