Hf3As2 is Stibnite structured and crystallizes in the orthorhombic Pnma space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. In the second Hf site, Hf(2) is bonded to two equivalent As(2) and three equivalent As(1) atoms to form edge-sharing HfAs5 square pyramids. In the third Hf site, Hf(3) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Hf(1), two equivalent Hf(3), and three equivalent Hf(2) atoms to form a mixture of distorted corner and edge-sharing AsHf7 pentagonal bipyramids. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Hf(2), three equivalent Hf(1), and three equivalent Hf(3) atoms.
Hf3As2 is Stibnite structured and crystallizes in the orthorhombic Pnma space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. Both Hf(1)-As(1) bond lengths are 2.71 Å. There are two shorter (2.72 Å) and one longer (2.80 Å) Hf(1)-As(2) bond length. In the second Hf site, Hf(2) is bonded to two equivalent As(2) and three equivalent As(1) atoms to form edge-sharing HfAs5 square pyramids. Both Hf(2)-As(2) bond lengths are 2.71 Å. There is one shorter (2.66 Å) and two longer (2.70 Å) Hf(2)-As(1) bond lengths. In the third Hf site, Hf(3) is bonded in a 5-coordinate geometry to two equivalent As(1) and three equivalent As(2) atoms. There is one shorter (2.69 Å) and one longer (2.83 Å) Hf(3)-As(1) bond length. There are two shorter (2.76 Å) and one longer (3.12 Å) Hf(3)-As(2) bond length. There are two inequivalent As sites. In the first As site, As(1) is bonded to two equivalent Hf(1), two equivalent Hf(3), and three equivalent Hf(2) atoms to form a mixture of distorted corner and edge-sharing AsHf7 pentagonal bipyramids. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Hf(2), three equivalent Hf(1), and three equivalent Hf(3) atoms.