Hf2(NiAs)3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 11-coordinate geometry to one Ni(2), two equivalent Ni(1), two equivalent Ni(3), one As(1), two equivalent As(2), and three equivalent As(3) atoms. In the second Hf site, Hf(2) is bonded in a 15-coordinate geometry to three equivalent Ni(1), three equivalent Ni(2), three equivalent Ni(3), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Hf(1), three equivalent Hf(2), one As(2), and three equivalent As(1) atoms to form distorted face-sharing NiHf5As4 tetrahedra. In the second Ni site, Ni(2) is bonded in a 10-coordinate geometry to one Hf(1), three equivalent Hf(2), two equivalent Ni(3), one As(1), one As(3), and two equivalent As(2) atoms. In the third Ni site, Ni(3) is bonded in a 4-coordinate geometry to two equivalent Hf(1), three equivalent Hf(2), two equivalent Ni(2), one As(2), one As(3), and two equivalent As(1) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to one Hf(1), two equivalent Hf(2), one Ni(2), two equivalent Ni(3), and three equivalent Ni(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Hf(1), two equivalent Hf(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Hf(2), three equivalent Hf(1), one Ni(2), and one Ni(3) atom.
Hf2(NiAs)3 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 11-coordinate geometry to one Ni(2), two equivalent Ni(1), two equivalent Ni(3), one As(1), two equivalent As(2), and three equivalent As(3) atoms. The Hf(1)-Ni(2) bond length is 2.81 Å. Both Hf(1)-Ni(1) bond lengths are 3.05 Å. Both Hf(1)-Ni(3) bond lengths are 2.96 Å. The Hf(1)-As(1) bond length is 2.68 Å. Both Hf(1)-As(2) bond lengths are 2.74 Å. There are two shorter (2.67 Å) and one longer (2.82 Å) Hf(1)-As(3) bond length. In the second Hf site, Hf(2) is bonded in a 15-coordinate geometry to three equivalent Ni(1), three equivalent Ni(2), three equivalent Ni(3), two equivalent As(1), two equivalent As(2), and two equivalent As(3) atoms. There are two shorter (3.10 Å) and one longer (3.33 Å) Hf(2)-Ni(1) bond length. All Hf(2)-Ni(2) bond lengths are 2.99 Å. There is one shorter (3.09 Å) and two longer (3.22 Å) Hf(2)-Ni(3) bond lengths. Both Hf(2)-As(1) bond lengths are 2.90 Å. Both Hf(2)-As(2) bond lengths are 2.81 Å. Both Hf(2)-As(3) bond lengths are 2.79 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent Hf(1), three equivalent Hf(2), one As(2), and three equivalent As(1) atoms to form distorted face-sharing NiHf5As4 tetrahedra. The Ni(1)-As(2) bond length is 2.33 Å. There is one shorter (2.31 Å) and two longer (2.38 Å) Ni(1)-As(1) bond lengths. In the second Ni site, Ni(2) is bonded in a 10-coordinate geometry to one Hf(1), three equivalent Hf(2), two equivalent Ni(3), one As(1), one As(3), and two equivalent As(2) atoms. Both Ni(2)-Ni(3) bond lengths are 2.54 Å. The Ni(2)-As(1) bond length is 2.32 Å. The Ni(2)-As(3) bond length is 2.29 Å. Both Ni(2)-As(2) bond lengths are 2.32 Å. In the third Ni site, Ni(3) is bonded in a 4-coordinate geometry to two equivalent Hf(1), three equivalent Hf(2), two equivalent Ni(2), one As(2), one As(3), and two equivalent As(1) atoms. The Ni(3)-As(2) bond length is 2.41 Å. The Ni(3)-As(3) bond length is 2.35 Å. Both Ni(3)-As(1) bond lengths are 2.38 Å. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to one Hf(1), two equivalent Hf(2), one Ni(2), two equivalent Ni(3), and three equivalent Ni(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Hf(1), two equivalent Hf(2), one Ni(1), one Ni(3), and two equivalent Ni(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to two equivalent Hf(2), three equivalent Hf(1), one Ni(2), and one Ni(3) atom.