Hf5CoAs3 crystallizes in the orthorhombic Pnma space group. There are five inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one As(3), two equivalent As(1), and two equivalent As(2) atoms to form distorted edge-sharing HfAs5 trigonal bipyramids. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one Co(1), two equivalent As(3), and three equivalent As(1) atoms. In the third Hf site, Hf(3) is bonded in a 6-coordinate geometry to three equivalent Co(1), one As(2), and three equivalent As(3) atoms. In the fourth Hf site, Hf(4) is bonded in a 6-coordinate geometry to two equivalent Co(1), one As(1), one As(3), and two equivalent As(2) atoms. In the fifth Hf site, Hf(5) is bonded in a 4-coordinate geometry to one Co(1), one As(1), and three equivalent As(2) atoms. Co(1) is bonded in a 9-coordinate geometry to one Hf(2), one Hf(5), two equivalent Hf(4), three equivalent Hf(3), and two equivalent As(3) atoms. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 9-coordinate geometry to one Hf(1), one Hf(4), two equivalent Hf(2), three equivalent Hf(3), and two equivalent Co(1) atoms. In the second As site, As(1) is bonded to one Hf(4), one Hf(5), two equivalent Hf(1), and three equivalent Hf(2) atoms to form distorted edge-sharing AsHf7 pentagonal bipyramids. In the third As site, As(2) is bonded in a 8-coordinate geometry to one Hf(3), two equivalent Hf(1), two equivalent Hf(4), and three equivalent Hf(5) atoms.
Hf5CoAs3 crystallizes in the orthorhombic Pnma space group. There are five inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one As(3), two equivalent As(1), and two equivalent As(2) atoms to form distorted edge-sharing HfAs5 trigonal bipyramids. The Hf(1)-As(3) bond length is 2.74 Å. Both Hf(1)-As(1) bond lengths are 2.73 Å. Both Hf(1)-As(2) bond lengths are 2.73 Å. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one Co(1), two equivalent As(3), and three equivalent As(1) atoms. The Hf(2)-Co(1) bond length is 2.85 Å. Both Hf(2)-As(3) bond lengths are 2.71 Å. There are two shorter (2.74 Å) and one longer (2.79 Å) Hf(2)-As(1) bond length. In the third Hf site, Hf(3) is bonded in a 6-coordinate geometry to three equivalent Co(1), one As(2), and three equivalent As(3) atoms. There are two shorter (2.70 Å) and one longer (3.03 Å) Hf(3)-Co(1) bond length. The Hf(3)-As(2) bond length is 2.79 Å. There are two shorter (2.71 Å) and one longer (2.81 Å) Hf(3)-As(3) bond length. In the fourth Hf site, Hf(4) is bonded in a 6-coordinate geometry to two equivalent Co(1), one As(1), one As(3), and two equivalent As(2) atoms. Both Hf(4)-Co(1) bond lengths are 2.51 Å. The Hf(4)-As(1) bond length is 2.72 Å. The Hf(4)-As(3) bond length is 2.82 Å. Both Hf(4)-As(2) bond lengths are 2.80 Å. In the fifth Hf site, Hf(5) is bonded in a 4-coordinate geometry to one Co(1), one As(1), and three equivalent As(2) atoms. The Hf(5)-Co(1) bond length is 2.57 Å. The Hf(5)-As(1) bond length is 2.74 Å. There are two shorter (2.78 Å) and one longer (3.27 Å) Hf(5)-As(2) bond length. Co(1) is bonded in a 9-coordinate geometry to one Hf(2), one Hf(5), two equivalent Hf(4), three equivalent Hf(3), and two equivalent As(3) atoms. Both Co(1)-As(3) bond lengths are 2.41 Å. There are three inequivalent As sites. In the first As site, As(3) is bonded in a 9-coordinate geometry to one Hf(1), one Hf(4), two equivalent Hf(2), three equivalent Hf(3), and two equivalent Co(1) atoms. In the second As site, As(1) is bonded to one Hf(4), one Hf(5), two equivalent Hf(1), and three equivalent Hf(2) atoms to form distorted edge-sharing AsHf7 pentagonal bipyramids. In the third As site, As(2) is bonded in a 8-coordinate geometry to one Hf(3), two equivalent Hf(1), two equivalent Hf(4), and three equivalent Hf(5) atoms.