Nb9Fe3Ge2 is beta Uranium-derived structured and crystallizes in the orthorhombic Fmmm space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent Nb(1), four equivalent Nb(4), four equivalent Nb(5), two equivalent Fe(1), and two equivalent Ge(2) atoms. In the second Nb site, Nb(2) is bonded in a 1-coordinate geometry to one Nb(5), three equivalent Nb(4), one Fe(1), two equivalent Fe(2), and one Ge(1) atom. In the third Nb site, Nb(3) is bonded in a 1-coordinate geometry to one Nb(4), three equivalent Nb(5), two equivalent Fe(3), one Ge(1), and one Ge(2) atom. In the fourth Nb site, Nb(4) is bonded in a 14-coordinate geometry to one Nb(3), one Nb(4), two equivalent Nb(1), two equivalent Nb(5), three equivalent Nb(2), two equivalent Fe(1), two equivalent Fe(2), and one Ge(2) atom. In the fifth Nb site, Nb(5) is bonded in a 14-coordinate geometry to one Nb(2), one Nb(5), two equivalent Nb(1), two equivalent Nb(4), three equivalent Nb(3), one Fe(1), two equivalent Fe(3), and two equivalent Ge(2) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(5), four equivalent Nb(4), and two equivalent Fe(2) atoms to form FeNb10Fe2 cuboctahedra that share corners with two equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with two equivalent Ge(1)Nb4Ge2 octahedra, edges with three equivalent Fe(1)Nb10Fe2 cuboctahedra, faces with four equivalent Fe(2)Nb8Fe4 cuboctahedra, and faces with four equivalent Ge(2)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 16°. In the second Fe site, Fe(2) is bonded to four equivalent Nb(2), four equivalent Nb(4), two equivalent Fe(1), and two equivalent Fe(2) atoms to form FeNb8Fe4 cuboctahedra that share corners with two equivalent Fe(2)Nb8Fe4 cuboctahedra, corners with four equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Ge(1)Nb4Ge2 octahedra, faces with two equivalent Fe(2)Nb8Fe4 cuboctahedra, and faces with four equivalent Fe(1)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 43°. In the third Fe site, Fe(3) is bonded to four equivalent Nb(3), four equivalent Nb(5), two equivalent Fe(3), and two equivalent Ge(2) atoms to form FeNb8Fe2Ge2 cuboctahedra that share corners with two equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with four equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with four equivalent Ge(1)Nb4Ge2 octahedra, faces with two equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, and faces with four equivalent Ge(2)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 43°. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to two equivalent Nb(2), two equivalent Nb(3), and two equivalent Ge(1) atoms to form distorted GeNb4Ge2 octahedra that share corners with two equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with two equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with four equivalent Fe(2)Nb8Fe4 cuboctahedra, and corners with two equivalent Ge(1)Nb4Ge2 octahedra. The corner-sharing octahedra are not tilted. In the second Ge site, Ge(2) is bonded to two equivalent Nb(1), two equivalent Nb(3), two equivalent Nb(4), four equivalent Nb(5), and two equivalent Fe(3) atoms to form GeNb10Fe2 cuboctahedra that share corners with two equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(2)Nb8Fe4 cuboctahedra, corners with two equivalent Ge(1)Nb4Ge2 octahedra, edges with three equivalent Ge(2)Nb10Fe2 cuboctahedra, faces with four equivalent Fe(1)Nb10Fe2 cuboctahedra, and faces with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra. The corner-sharing octahedral tilt angles are 17°.
Nb9Fe3Ge2 is beta Uranium-derived structured and crystallizes in the orthorhombic Fmmm space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to two equivalent Nb(1), four equivalent Nb(4), four equivalent Nb(5), two equivalent Fe(1), and two equivalent Ge(2) atoms. There is one shorter (2.46 Å) and one longer (2.58 Å) Nb(1)-Nb(1) bond length. All Nb(1)-Nb(4) bond lengths are 3.18 Å. All Nb(1)-Nb(5) bond lengths are 3.19 Å. Both Nb(1)-Fe(1) bond lengths are 2.84 Å. Both Nb(1)-Ge(2) bond lengths are 2.81 Å. In the second Nb site, Nb(2) is bonded in a 1-coordinate geometry to one Nb(5), three equivalent Nb(4), one Fe(1), two equivalent Fe(2), and one Ge(1) atom. The Nb(2)-Nb(5) bond length is 2.71 Å. There are two shorter (3.06 Å) and one longer (3.07 Å) Nb(2)-Nb(4) bond length. The Nb(2)-Fe(1) bond length is 2.72 Å. Both Nb(2)-Fe(2) bond lengths are 2.72 Å. The Nb(2)-Ge(1) bond length is 2.60 Å. In the third Nb site, Nb(3) is bonded in a 1-coordinate geometry to one Nb(4), three equivalent Nb(5), two equivalent Fe(3), one Ge(1), and one Ge(2) atom. The Nb(3)-Nb(4) bond length is 2.76 Å. There are two shorter (3.05 Å) and one longer (3.07 Å) Nb(3)-Nb(5) bond length. Both Nb(3)-Fe(3) bond lengths are 2.73 Å. The Nb(3)-Ge(1) bond length is 2.56 Å. The Nb(3)-Ge(2) bond length is 2.78 Å. In the fourth Nb site, Nb(4) is bonded in a 14-coordinate geometry to one Nb(3), one Nb(4), two equivalent Nb(1), two equivalent Nb(5), three equivalent Nb(2), two equivalent Fe(1), two equivalent Fe(2), and one Ge(2) atom. The Nb(4)-Nb(4) bond length is 2.60 Å. Both Nb(4)-Nb(5) bond lengths are 3.12 Å. Both Nb(4)-Fe(1) bond lengths are 2.84 Å. Both Nb(4)-Fe(2) bond lengths are 2.82 Å. The Nb(4)-Ge(2) bond length is 2.86 Å. In the fifth Nb site, Nb(5) is bonded in a 14-coordinate geometry to one Nb(2), one Nb(5), two equivalent Nb(1), two equivalent Nb(4), three equivalent Nb(3), one Fe(1), two equivalent Fe(3), and two equivalent Ge(2) atoms. The Nb(5)-Nb(5) bond length is 2.66 Å. The Nb(5)-Fe(1) bond length is 2.89 Å. Both Nb(5)-Fe(3) bond lengths are 2.84 Å. Both Nb(5)-Ge(2) bond lengths are 2.85 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), two equivalent Nb(5), four equivalent Nb(4), and two equivalent Fe(2) atoms to form FeNb10Fe2 cuboctahedra that share corners with two equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with two equivalent Ge(1)Nb4Ge2 octahedra, edges with three equivalent Fe(1)Nb10Fe2 cuboctahedra, faces with four equivalent Fe(2)Nb8Fe4 cuboctahedra, and faces with four equivalent Ge(2)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 16°. Both Fe(1)-Fe(2) bond lengths are 2.54 Å. In the second Fe site, Fe(2) is bonded to four equivalent Nb(2), four equivalent Nb(4), two equivalent Fe(1), and two equivalent Fe(2) atoms to form FeNb8Fe4 cuboctahedra that share corners with two equivalent Fe(2)Nb8Fe4 cuboctahedra, corners with four equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Ge(1)Nb4Ge2 octahedra, faces with two equivalent Fe(2)Nb8Fe4 cuboctahedra, and faces with four equivalent Fe(1)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 43°. Both Fe(2)-Fe(2) bond lengths are 2.52 Å. In the third Fe site, Fe(3) is bonded to four equivalent Nb(3), four equivalent Nb(5), two equivalent Fe(3), and two equivalent Ge(2) atoms to form FeNb8Fe2Ge2 cuboctahedra that share corners with two equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with four equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with four equivalent Ge(1)Nb4Ge2 octahedra, faces with two equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, and faces with four equivalent Ge(2)Nb10Fe2 cuboctahedra. The corner-sharing octahedral tilt angles are 43°. Both Fe(3)-Fe(3) bond lengths are 2.52 Å. Both Fe(3)-Ge(2) bond lengths are 2.61 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to two equivalent Nb(2), two equivalent Nb(3), and two equivalent Ge(1) atoms to form distorted GeNb4Ge2 octahedra that share corners with two equivalent Fe(1)Nb10Fe2 cuboctahedra, corners with two equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra, corners with four equivalent Fe(2)Nb8Fe4 cuboctahedra, and corners with two equivalent Ge(1)Nb4Ge2 octahedra. The corner-sharing octahedra are not tilted. Both Ge(1)-Ge(1) bond lengths are 2.52 Å. In the second Ge site, Ge(2) is bonded to two equivalent Nb(1), two equivalent Nb(3), two equivalent Nb(4), four equivalent Nb(5), and two equivalent Fe(3) atoms to form GeNb10Fe2 cuboctahedra that share corners with two equivalent Ge(2)Nb10Fe2 cuboctahedra, corners with four equivalent Fe(2)Nb8Fe4 cuboctahedra, corners with two equivalent Ge(1)Nb4Ge2 octahedra, edges with three equivalent Ge(2)Nb10Fe2 cuboctahedra, faces with four equivalent Fe(1)Nb10Fe2 cuboctahedra, and faces with four equivalent Fe(3)Nb8Fe2Ge2 cuboctahedra. The corner-sharing octahedral tilt angles are 17°.