NbCr4Al is Hexagonal Laves-derived structured and crystallizes in the trigonal P-3m1 space group. Nb(1) is bonded in a 16-coordinate geometry to three equivalent Nb(1), three equivalent Cr(2), nine equivalent Cr(3), and one Al(1) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Cr(3) and six equivalent Al(1) atoms to form CrAl6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(1)Al6Cr6 cuboctahedra, faces with two equivalent Cr(2)Nb6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. In the second Cr site, Cr(2) is bonded to six equivalent Nb(1) and six equivalent Cr(3) atoms to form CrNb6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with two equivalent Cr(1)Al6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. In the third Cr site, Cr(3) is bonded to three equivalent Nb(1), one Cr(1), one Cr(2), four equivalent Cr(3), and three equivalent Al(1) atoms to form CrNb3Al3Cr6 cuboctahedra that share corners with two equivalent Cr(1)Al6Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with fourteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(1)Al6Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, and faces with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. Al(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Cr(1), nine equivalent Cr(3), and three equivalent Al(1) atoms.
NbCr4Al is Hexagonal Laves-derived structured and crystallizes in the trigonal P-3m1 space group. Nb(1) is bonded in a 16-coordinate geometry to three equivalent Nb(1), three equivalent Cr(2), nine equivalent Cr(3), and one Al(1) atom. All Nb(1)-Nb(1) bond lengths are 2.99 Å. All Nb(1)-Cr(2) bond lengths are 2.87 Å. There are three shorter (2.84 Å) and six longer (2.88 Å) Nb(1)-Cr(3) bond lengths. The Nb(1)-Al(1) bond length is 2.91 Å. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to six equivalent Cr(3) and six equivalent Al(1) atoms to form CrAl6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(1)Al6Cr6 cuboctahedra, faces with two equivalent Cr(2)Nb6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. All Cr(1)-Cr(3) bond lengths are 2.40 Å. All Cr(1)-Al(1) bond lengths are 2.87 Å. In the second Cr site, Cr(2) is bonded to six equivalent Nb(1) and six equivalent Cr(3) atoms to form CrNb6Cr6 cuboctahedra that share corners with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(2)Nb6Cr6 cuboctahedra, faces with two equivalent Cr(1)Al6Cr6 cuboctahedra, and faces with eighteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. All Cr(2)-Cr(3) bond lengths are 2.47 Å. In the third Cr site, Cr(3) is bonded to three equivalent Nb(1), one Cr(1), one Cr(2), four equivalent Cr(3), and three equivalent Al(1) atoms to form CrNb3Al3Cr6 cuboctahedra that share corners with two equivalent Cr(1)Al6Cr6 cuboctahedra, corners with two equivalent Cr(2)Nb6Cr6 cuboctahedra, corners with fourteen equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, edges with six equivalent Cr(3)Nb3Al3Cr6 cuboctahedra, faces with three equivalent Cr(1)Al6Cr6 cuboctahedra, faces with three equivalent Cr(2)Nb6Cr6 cuboctahedra, and faces with twelve equivalent Cr(3)Nb3Al3Cr6 cuboctahedra. There are two shorter (2.39 Å) and two longer (2.51 Å) Cr(3)-Cr(3) bond lengths. There is one shorter (2.77 Å) and two longer (2.83 Å) Cr(3)-Al(1) bond lengths. Al(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Cr(1), nine equivalent Cr(3), and three equivalent Al(1) atoms. All Al(1)-Al(1) bond lengths are 3.00 Å.