Hf2Ni3Si4 crystallizes in the orthorhombic Cmce space group. Hf(1) is bonded in a 9-coordinate geometry to three equivalent Ni(2), four equivalent Ni(1), four equivalent Si(1), and four equivalent Si(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 11-coordinate geometry to four equivalent Hf(1), two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to six equivalent Hf(1), two equivalent Si(1), and four equivalent Si(2) atoms to form a mixture of distorted edge and face-sharing NiHf6Si6 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to four equivalent Hf(1), one Ni(2), four equivalent Ni(1), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to four equivalent Hf(1), one Ni(1), two equivalent Ni(2), and two equivalent Si(1) atoms.
Hf2Ni3Si4 crystallizes in the orthorhombic Cmce space group. Hf(1) is bonded in a 9-coordinate geometry to three equivalent Ni(2), four equivalent Ni(1), four equivalent Si(1), and four equivalent Si(2) atoms. There are two shorter (3.01 Å) and one longer (3.09 Å) Hf(1)-Ni(2) bond length. There are two shorter (2.80 Å) and two longer (3.19 Å) Hf(1)-Ni(1) bond lengths. There are a spread of Hf(1)-Si(1) bond distances ranging from 2.80-3.02 Å. There are two shorter (2.76 Å) and two longer (2.79 Å) Hf(1)-Si(2) bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 11-coordinate geometry to four equivalent Hf(1), two equivalent Ni(1), one Si(2), and four equivalent Si(1) atoms. Both Ni(1)-Ni(1) bond lengths are 2.57 Å. The Ni(1)-Si(2) bond length is 2.27 Å. All Ni(1)-Si(1) bond lengths are 2.35 Å. In the second Ni site, Ni(2) is bonded to six equivalent Hf(1), two equivalent Si(1), and four equivalent Si(2) atoms to form a mixture of distorted edge and face-sharing NiHf6Si6 cuboctahedra. Both Ni(2)-Si(1) bond lengths are 2.47 Å. All Ni(2)-Si(2) bond lengths are 2.30 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to four equivalent Hf(1), one Ni(2), four equivalent Ni(1), and two equivalent Si(2) atoms. Both Si(1)-Si(2) bond lengths are 2.78 Å. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to four equivalent Hf(1), one Ni(1), two equivalent Ni(2), and two equivalent Si(1) atoms.