Fe7Nb6 is Frank-Kasper $\mu$ Phase structured and crystallizes in the trigonal R-3m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 15-coordinate geometry to three equivalent Nb(1), six equivalent Nb(3), and six equivalent Fe(2) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Nb(2), three equivalent Fe(1), and nine equivalent Fe(2) atoms. In the third Nb site, Nb(3) is bonded in a 14-coordinate geometry to one Nb(2), one Nb(3), six equivalent Nb(1), and six equivalent Fe(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent Nb(2) and six equivalent Fe(2) atoms to form FeNb6Fe6 cuboctahedra that share corners with twelve equivalent Fe(2)Nb7Fe5 cuboctahedra, edges with six equivalent Fe(1)Nb6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(2)Nb7Fe5 cuboctahedra. In the second Fe site, Fe(2) is bonded to two equivalent Nb(1), two equivalent Nb(3), three equivalent Nb(2), one Fe(1), and four equivalent Fe(2) atoms to form FeNb7Fe5 cuboctahedra that share corners with two equivalent Fe(1)Nb6Fe6 cuboctahedra, corners with thirteen equivalent Fe(2)Nb7Fe5 cuboctahedra, edges with five equivalent Fe(2)Nb7Fe5 cuboctahedra, faces with three equivalent Fe(1)Nb6Fe6 cuboctahedra, and faces with ten equivalent Fe(2)Nb7Fe5 cuboctahedra.
Fe7Nb6 is Frank-Kasper $\mu$ Phase structured and crystallizes in the trigonal R-3m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 15-coordinate geometry to three equivalent Nb(1), six equivalent Nb(3), and six equivalent Fe(2) atoms. All Nb(1)-Nb(1) bond lengths are 2.82 Å. There are three shorter (3.11 Å) and three longer (3.12 Å) Nb(1)-Nb(3) bond lengths. All Nb(1)-Fe(2) bond lengths are 2.80 Å. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Nb(2), three equivalent Fe(1), and nine equivalent Fe(2) atoms. The Nb(2)-Nb(3) bond length is 2.72 Å. All Nb(2)-Nb(2) bond lengths are 2.90 Å. All Nb(2)-Fe(1) bond lengths are 2.84 Å. There are three shorter (2.70 Å) and six longer (2.93 Å) Nb(2)-Fe(2) bond lengths. In the third Nb site, Nb(3) is bonded in a 14-coordinate geometry to one Nb(2), one Nb(3), six equivalent Nb(1), and six equivalent Fe(2) atoms. The Nb(3)-Nb(3) bond length is 2.65 Å. All Nb(3)-Fe(2) bond lengths are 2.68 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent Nb(2) and six equivalent Fe(2) atoms to form FeNb6Fe6 cuboctahedra that share corners with twelve equivalent Fe(2)Nb7Fe5 cuboctahedra, edges with six equivalent Fe(1)Nb6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(2)Nb7Fe5 cuboctahedra. All Fe(1)-Fe(2) bond lengths are 2.41 Å. In the second Fe site, Fe(2) is bonded to two equivalent Nb(1), two equivalent Nb(3), three equivalent Nb(2), one Fe(1), and four equivalent Fe(2) atoms to form FeNb7Fe5 cuboctahedra that share corners with two equivalent Fe(1)Nb6Fe6 cuboctahedra, corners with thirteen equivalent Fe(2)Nb7Fe5 cuboctahedra, edges with five equivalent Fe(2)Nb7Fe5 cuboctahedra, faces with three equivalent Fe(1)Nb6Fe6 cuboctahedra, and faces with ten equivalent Fe(2)Nb7Fe5 cuboctahedra. There are two shorter (2.42 Å) and two longer (2.47 Å) Fe(2)-Fe(2) bond lengths.