Hf6Fe16Si7 crystallizes in the cubic Fm-3m space group. Hf(1) is bonded in a 12-coordinate geometry to four equivalent Fe(1), four equivalent Fe(2), and four equivalent Si(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 13-coordinate geometry to three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(2), one Si(2), and three equivalent Si(1) atoms. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(2), and three equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a body-centered cubic geometry to eight equivalent Fe(1) atoms. In the second Si site, Si(1) is bonded to four equivalent Hf(1), four equivalent Fe(1), and four equivalent Fe(2) atoms to form a mixture of corner and face-sharing SiHf4Fe8 cuboctahedra.
Hf6Fe16Si7 crystallizes in the cubic Fm-3m space group. Hf(1) is bonded in a 12-coordinate geometry to four equivalent Fe(1), four equivalent Fe(2), and four equivalent Si(1) atoms. All Hf(1)-Fe(1) bond lengths are 2.85 Å. All Hf(1)-Fe(2) bond lengths are 2.86 Å. All Hf(1)-Si(1) bond lengths are 2.94 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 13-coordinate geometry to three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(2), one Si(2), and three equivalent Si(1) atoms. All Fe(1)-Fe(1) bond lengths are 2.65 Å. All Fe(1)-Fe(2) bond lengths are 2.61 Å. The Fe(1)-Si(2) bond length is 2.29 Å. All Fe(1)-Si(1) bond lengths are 2.56 Å. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(2), and three equivalent Si(1) atoms. All Fe(2)-Fe(2) bond lengths are 2.44 Å. All Fe(2)-Si(1) bond lengths are 2.35 Å. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a body-centered cubic geometry to eight equivalent Fe(1) atoms. In the second Si site, Si(1) is bonded to four equivalent Hf(1), four equivalent Fe(1), and four equivalent Fe(2) atoms to form a mixture of corner and face-sharing SiHf4Fe8 cuboctahedra.