Zr4NbAl3 crystallizes in the monoclinic C2/m space group. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 8-coordinate geometry to two equivalent Nb(1), one Al(3), two equivalent Al(1), and three equivalent Al(2) atoms. In the second Zr site, Zr(2) is bonded in a 6-coordinate geometry to two equivalent Nb(1), one Al(3), two equivalent Al(1), and three equivalent Al(2) atoms. In the third Zr site, Zr(3) is bonded in a 7-coordinate geometry to three equivalent Nb(1), one Al(2), two equivalent Al(1), and three equivalent Al(3) atoms. In the fourth Zr site, Zr(4) is bonded in a 6-coordinate geometry to two equivalent Zr(4), two equivalent Nb(1), two equivalent Al(2), and two equivalent Al(3) atoms. Nb(1) is bonded in a 15-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(4), three equivalent Zr(3), one Al(2), two equivalent Al(1), and three equivalent Al(3) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(3), two equivalent Nb(1), and two equivalent Al(1) atoms. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Zr(3), two equivalent Zr(4), three equivalent Zr(1), three equivalent Zr(2), and one Nb(1) atom. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Zr(1), one Zr(2), two equivalent Zr(4), three equivalent Zr(3), and three equivalent Nb(1) atoms.
Zr4NbAl3 crystallizes in the monoclinic C2/m space group. There are four inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 8-coordinate geometry to two equivalent Nb(1), one Al(3), two equivalent Al(1), and three equivalent Al(2) atoms. Both Zr(1)-Nb(1) bond lengths are 3.14 Å. The Zr(1)-Al(3) bond length is 2.93 Å. Both Zr(1)-Al(1) bond lengths are 2.88 Å. There is one shorter (2.95 Å) and two longer (3.09 Å) Zr(1)-Al(2) bond lengths. In the second Zr site, Zr(2) is bonded in a 6-coordinate geometry to two equivalent Nb(1), one Al(3), two equivalent Al(1), and three equivalent Al(2) atoms. There is one shorter (3.54 Å) and one longer (3.57 Å) Zr(2)-Nb(1) bond length. The Zr(2)-Al(3) bond length is 2.95 Å. Both Zr(2)-Al(1) bond lengths are 2.87 Å. There is one shorter (2.88 Å) and two longer (3.13 Å) Zr(2)-Al(2) bond lengths. In the third Zr site, Zr(3) is bonded in a 7-coordinate geometry to three equivalent Nb(1), one Al(2), two equivalent Al(1), and three equivalent Al(3) atoms. There is one shorter (3.16 Å) and two longer (3.42 Å) Zr(3)-Nb(1) bond lengths. The Zr(3)-Al(2) bond length is 3.01 Å. Both Zr(3)-Al(1) bond lengths are 2.91 Å. There is one shorter (2.83 Å) and two longer (3.08 Å) Zr(3)-Al(3) bond lengths. In the fourth Zr site, Zr(4) is bonded in a 6-coordinate geometry to two equivalent Zr(4), two equivalent Nb(1), two equivalent Al(2), and two equivalent Al(3) atoms. There is one shorter (2.66 Å) and one longer (2.67 Å) Zr(4)-Zr(4) bond length. Both Zr(4)-Nb(1) bond lengths are 3.53 Å. Both Zr(4)-Al(2) bond lengths are 2.86 Å. Both Zr(4)-Al(3) bond lengths are 2.91 Å. Nb(1) is bonded in a 15-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(4), three equivalent Zr(3), one Al(2), two equivalent Al(1), and three equivalent Al(3) atoms. The Nb(1)-Al(2) bond length is 2.91 Å. Both Nb(1)-Al(1) bond lengths are 2.81 Å. There is one shorter (2.84 Å) and two longer (3.14 Å) Nb(1)-Al(3) bond lengths. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to two equivalent Zr(1), two equivalent Zr(2), two equivalent Zr(3), two equivalent Nb(1), and two equivalent Al(1) atoms. There is one shorter (2.64 Å) and one longer (2.69 Å) Al(1)-Al(1) bond length. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Zr(3), two equivalent Zr(4), three equivalent Zr(1), three equivalent Zr(2), and one Nb(1) atom. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Zr(1), one Zr(2), two equivalent Zr(4), three equivalent Zr(3), and three equivalent Nb(1) atoms.