Y2Fe17 crystallizes in the trigonal R-3m space group. Y(1) is bonded in a 19-coordinate geometry to one Fe(4), three equivalent Fe(1), six equivalent Fe(2), and nine equivalent Fe(3) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Y(1), two equivalent Fe(4), four equivalent Fe(2), and four equivalent Fe(3) atoms to form FeY2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Y2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Y3Fe9 cuboctahedra, edges with six equivalent Fe(3)Y3Fe9 cuboctahedra, faces with four equivalent Fe(1)Y2Fe10 cuboctahedra, and faces with six equivalent Fe(3)Y3Fe9 cuboctahedra. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to two equivalent Y(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms. In the third Fe site, Fe(3) is bonded to three equivalent Y(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms to form FeY3Fe9 cuboctahedra that share corners with five equivalent Fe(1)Y2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Y3Fe9 cuboctahedra, edges with three equivalent Fe(1)Y2Fe10 cuboctahedra, edges with five equivalent Fe(3)Y3Fe9 cuboctahedra, faces with three equivalent Fe(1)Y2Fe10 cuboctahedra, and faces with seven equivalent Fe(3)Y3Fe9 cuboctahedra. In the fourth Fe site, Fe(4) is bonded in a 14-coordinate geometry to one Y(1), one Fe(4), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(2) atoms.
Y2Fe17 crystallizes in the trigonal R-3m space group. Y(1) is bonded in a 19-coordinate geometry to one Fe(4), three equivalent Fe(1), six equivalent Fe(2), and nine equivalent Fe(3) atoms. The Y(1)-Fe(4) bond length is 3.00 Å. All Y(1)-Fe(1) bond lengths are 3.26 Å. All Y(1)-Fe(2) bond lengths are 3.04 Å. There are a spread of Y(1)-Fe(3) bond distances ranging from 3.08-3.26 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Y(1), two equivalent Fe(4), four equivalent Fe(2), and four equivalent Fe(3) atoms to form FeY2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Y2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Y3Fe9 cuboctahedra, edges with six equivalent Fe(3)Y3Fe9 cuboctahedra, faces with four equivalent Fe(1)Y2Fe10 cuboctahedra, and faces with six equivalent Fe(3)Y3Fe9 cuboctahedra. Both Fe(1)-Fe(4) bond lengths are 2.62 Å. All Fe(1)-Fe(2) bond lengths are 2.43 Å. All Fe(1)-Fe(3) bond lengths are 2.47 Å. In the second Fe site, Fe(2) is bonded in a 12-coordinate geometry to two equivalent Y(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms. Both Fe(2)-Fe(2) bond lengths are 2.51 Å. Both Fe(2)-Fe(4) bond lengths are 2.78 Å. There are two shorter (2.55 Å) and two longer (2.60 Å) Fe(2)-Fe(3) bond lengths. In the third Fe site, Fe(3) is bonded to three equivalent Y(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms to form FeY3Fe9 cuboctahedra that share corners with five equivalent Fe(1)Y2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Y3Fe9 cuboctahedra, edges with three equivalent Fe(1)Y2Fe10 cuboctahedra, edges with five equivalent Fe(3)Y3Fe9 cuboctahedra, faces with three equivalent Fe(1)Y2Fe10 cuboctahedra, and faces with seven equivalent Fe(3)Y3Fe9 cuboctahedra. The Fe(3)-Fe(4) bond length is 2.66 Å. Both Fe(3)-Fe(3) bond lengths are 2.49 Å. In the fourth Fe site, Fe(4) is bonded in a 14-coordinate geometry to one Y(1), one Fe(4), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(2) atoms. The Fe(4)-Fe(4) bond length is 2.38 Å.