Hf2AlSi crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to three equivalent Al(1) and four equivalent Si(1) atoms. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to four equivalent Al(1) and three equivalent Si(1) atoms. Al(1) is bonded in a 9-coordinate geometry to three equivalent Hf(1), four equivalent Hf(2), and two equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to three equivalent Hf(2), four equivalent Hf(1), and two equivalent Al(1) atoms.
Hf2AlSi crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 7-coordinate geometry to three equivalent Al(1) and four equivalent Si(1) atoms. There is one shorter (2.78 Å) and two longer (2.95 Å) Hf(1)-Al(1) bond lengths. All Hf(1)-Si(1) bond lengths are 2.77 Å. In the second Hf site, Hf(2) is bonded in a 7-coordinate geometry to four equivalent Al(1) and three equivalent Si(1) atoms. All Hf(2)-Al(1) bond lengths are 2.78 Å. There is one shorter (2.77 Å) and two longer (2.96 Å) Hf(2)-Si(1) bond lengths. Al(1) is bonded in a 9-coordinate geometry to three equivalent Hf(1), four equivalent Hf(2), and two equivalent Si(1) atoms. Both Al(1)-Si(1) bond lengths are 2.48 Å. Si(1) is bonded in a 9-coordinate geometry to three equivalent Hf(2), four equivalent Hf(1), and two equivalent Al(1) atoms.