Hf3TaFe8 is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(2), three equivalent Ta(1), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(4) atoms. In the second Hf site, Hf(2) is bonded in a 12-coordinate geometry to one Hf(1), three equivalent Hf(3), three equivalent Fe(2), three equivalent Fe(3), and six equivalent Fe(4) atoms. In the third Hf site, Hf(3) is bonded in a 16-coordinate geometry to three equivalent Hf(2), one Ta(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms. Ta(1) is bonded in a 16-coordinate geometry to one Hf(3), three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(4), and six equivalent Fe(3) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Hf(1), three equivalent Ta(1), three equivalent Fe(3), and three equivalent Fe(4) atoms to form FeHf3Ta3Fe6 cuboctahedra that share corners with six equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with six equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with six equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with two equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with nine equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with nine equivalent Fe(4)Hf5TaFe6 cuboctahedra. In the second Fe site, Fe(2) is bonded to three equivalent Hf(2), three equivalent Hf(3), three equivalent Fe(3), and three equivalent Fe(4) atoms to form FeHf6Fe6 cuboctahedra that share corners with six equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with six equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with six equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with nine equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with nine equivalent Fe(4)Hf5TaFe6 cuboctahedra. In the third Fe site, Fe(3) is bonded to one Hf(1), one Hf(2), two equivalent Hf(3), two equivalent Ta(1), one Fe(1), one Fe(2), and four equivalent Fe(3) atoms to form FeHf4Ta2Fe6 cuboctahedra that share corners with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, corners with two equivalent Fe(2)Hf6Fe6 cuboctahedra, corners with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with ten equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with two equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, edges with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, faces with three equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with three equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, and faces with eight equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra. In the fourth Fe site, Fe(4) is bonded to one Hf(3), two equivalent Hf(1), two equivalent Hf(2), one Ta(1), one Fe(1), one Fe(2), and four equivalent Fe(4) atoms to form FeHf5TaFe6 cuboctahedra that share corners with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, corners with two equivalent Fe(2)Hf6Fe6 cuboctahedra, corners with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, corners with ten equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, edges with two equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, faces with three equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with three equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with eight equivalent Fe(4)Hf5TaFe6 cuboctahedra.
Hf3TaFe8 is Hexagonal Laves-derived structured and crystallizes in the trigonal P3m1 space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded in a 16-coordinate geometry to one Hf(2), three equivalent Ta(1), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(4) atoms. The Hf(1)-Hf(2) bond length is 3.06 Å. All Hf(1)-Ta(1) bond lengths are 3.01 Å. All Hf(1)-Fe(1) bond lengths are 2.89 Å. All Hf(1)-Fe(3) bond lengths are 2.85 Å. All Hf(1)-Fe(4) bond lengths are 2.90 Å. In the second Hf site, Hf(2) is bonded in a 12-coordinate geometry to one Hf(1), three equivalent Hf(3), three equivalent Fe(2), three equivalent Fe(3), and six equivalent Fe(4) atoms. All Hf(2)-Hf(3) bond lengths are 3.03 Å. All Hf(2)-Fe(2) bond lengths are 2.90 Å. All Hf(2)-Fe(3) bond lengths are 2.90 Å. All Hf(2)-Fe(4) bond lengths are 2.91 Å. In the third Hf site, Hf(3) is bonded in a 16-coordinate geometry to three equivalent Hf(2), one Ta(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms. The Hf(3)-Ta(1) bond length is 3.02 Å. All Hf(3)-Fe(2) bond lengths are 2.90 Å. All Hf(3)-Fe(4) bond lengths are 2.92 Å. All Hf(3)-Fe(3) bond lengths are 2.90 Å. Ta(1) is bonded in a 16-coordinate geometry to one Hf(3), three equivalent Hf(1), three equivalent Fe(1), three equivalent Fe(4), and six equivalent Fe(3) atoms. All Ta(1)-Fe(1) bond lengths are 2.89 Å. All Ta(1)-Fe(4) bond lengths are 2.86 Å. All Ta(1)-Fe(3) bond lengths are 2.90 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent Hf(1), three equivalent Ta(1), three equivalent Fe(3), and three equivalent Fe(4) atoms to form FeHf3Ta3Fe6 cuboctahedra that share corners with six equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with six equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with six equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with two equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with nine equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with nine equivalent Fe(4)Hf5TaFe6 cuboctahedra. All Fe(1)-Fe(3) bond lengths are 2.46 Å. All Fe(1)-Fe(4) bond lengths are 2.46 Å. In the second Fe site, Fe(2) is bonded to three equivalent Hf(2), three equivalent Hf(3), three equivalent Fe(3), and three equivalent Fe(4) atoms to form FeHf6Fe6 cuboctahedra that share corners with six equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with six equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with six equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with nine equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with nine equivalent Fe(4)Hf5TaFe6 cuboctahedra. All Fe(2)-Fe(3) bond lengths are 2.49 Å. All Fe(2)-Fe(4) bond lengths are 2.49 Å. In the third Fe site, Fe(3) is bonded to one Hf(1), one Hf(2), two equivalent Hf(3), two equivalent Ta(1), one Fe(1), one Fe(2), and four equivalent Fe(3) atoms to form FeHf4Ta2Fe6 cuboctahedra that share corners with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, corners with two equivalent Fe(2)Hf6Fe6 cuboctahedra, corners with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, corners with ten equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with two equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, edges with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, faces with three equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with three equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, and faces with eight equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra. There are two shorter (2.45 Å) and two longer (2.49 Å) Fe(3)-Fe(3) bond lengths. In the fourth Fe site, Fe(4) is bonded to one Hf(3), two equivalent Hf(1), two equivalent Hf(2), one Ta(1), one Fe(1), one Fe(2), and four equivalent Fe(4) atoms to form FeHf5TaFe6 cuboctahedra that share corners with two equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, corners with two equivalent Fe(2)Hf6Fe6 cuboctahedra, corners with four equivalent Fe(4)Hf5TaFe6 cuboctahedra, corners with ten equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, edges with two equivalent Fe(4)Hf5TaFe6 cuboctahedra, edges with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, faces with three equivalent Fe(1)Hf3Ta3Fe6 cuboctahedra, faces with three equivalent Fe(2)Hf6Fe6 cuboctahedra, faces with four equivalent Fe(3)Hf4Ta2Fe6 cuboctahedra, and faces with eight equivalent Fe(4)Hf5TaFe6 cuboctahedra. There are two shorter (2.45 Å) and two longer (2.49 Å) Fe(4)-Fe(4) bond lengths.