NbCoAl crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Co(1); two equivalent Co(3); four equivalent Co(2); two equivalent Al(2); and three equivalent Al(1) atoms. In the third Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Nb(1), one Co(1), two equivalent Co(3), four equivalent Co(2), two equivalent Al(2), and three equivalent Al(1) atoms. In the fourth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. In the fifth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two Nb(2,2); four Nb(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form distorted CoNb6Al6 cuboctahedra that share corners with two equivalent Co(3)Nb6Al2Co4 cuboctahedra, corners with four equivalent Co(1)Nb6Al6 cuboctahedra, corners with eight equivalent Co(2)Nb6Al2Co4 cuboctahedra, edges with two equivalent Co(1)Nb6Al6 cuboctahedra, edges with four equivalent Co(3)Nb6Al2Co4 cuboctahedra, and faces with four equivalent Co(2)Nb6Al2Co4 cuboctahedra. In the second Co site, Co(2) is bonded to two Nb(1,1); four Nb(2,2); two equivalent Co(2); two equivalent Co(3); and two equivalent Al(1) atoms to form distorted CoNb6Al2Co4 cuboctahedra that share corners with four equivalent Co(2)Nb6Al2Co4 cuboctahedra, corners with four equivalent Co(1)Nb6Al6 cuboctahedra, edges with two equivalent Co(2)Nb6Al2Co4 cuboctahedra, faces with two equivalent Co(1)Nb6Al6 cuboctahedra, faces with four equivalent Co(2)Nb6Al2Co4 cuboctahedra, and faces with four equivalent Co(3)Nb6Al2Co4 cuboctahedra. In the third Co site, Co(3) is bonded to two Nb(1,1); four Nb(2,2); four equivalent Co(2); and two equivalent Al(1) atoms to form distorted CoNb6Al2Co4 cuboctahedra that share corners with two equivalent Co(1)Nb6Al6 cuboctahedra, corners with four equivalent Co(3)Nb6Al2Co4 cuboctahedra, edges with two equivalent Co(3)Nb6Al2Co4 cuboctahedra, edges with four equivalent Co(1)Nb6Al6 cuboctahedra, and faces with eight equivalent Co(2)Nb6Al2Co4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to three Nb(1,1); three equivalent Nb(2); one Co(1); one Co(3); two equivalent Co(2); and two equivalent Al(2) atoms. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two Nb(2,2); four Nb(1,1,1); two equivalent Co(1); two equivalent Al(1); and two equivalent Al(2) atoms.
NbCoAl crystallizes in the orthorhombic Amm2 space group. There are five inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. The Nb(1)-Nb(1) bond length is 3.27 Å. There is one shorter (2.96 Å) and two longer (3.05 Å) Nb(1)-Nb(2) bond lengths. The Nb(1)-Co(3) bond length is 2.72 Å. Both Nb(1)-Co(1) bond lengths are 3.00 Å. Both Nb(1)-Co(2) bond lengths are 2.73 Å. There are two shorter (2.88 Å) and one longer (2.93 Å) Nb(1)-Al(1) bond length. There are two shorter (2.92 Å) and two longer (2.99 Å) Nb(1)-Al(2) bond lengths. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2); three Nb(1,1); one Co(1); two equivalent Co(3); four equivalent Co(2); two equivalent Al(2); and three equivalent Al(1) atoms. The Nb(2)-Nb(2) bond length is 2.79 Å. Both Nb(2)-Nb(1) bond lengths are 3.05 Å. The Nb(2)-Co(1) bond length is 2.98 Å. Both Nb(2)-Co(3) bond lengths are 2.87 Å. There are two shorter (2.80 Å) and two longer (2.86 Å) Nb(2)-Co(2) bond lengths. Both Nb(2)-Al(2) bond lengths are 2.93 Å. There is one shorter (2.82 Å) and two longer (2.95 Å) Nb(2)-Al(1) bond lengths. In the third Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Nb(1), one Co(1), two equivalent Co(3), four equivalent Co(2), two equivalent Al(2), and three equivalent Al(1) atoms. There is one shorter (2.96 Å) and two longer (3.05 Å) Nb(2)-Nb(1) bond lengths. The Nb(2)-Co(1) bond length is 2.98 Å. Both Nb(2)-Co(3) bond lengths are 2.87 Å. There are two shorter (2.80 Å) and two longer (2.86 Å) Nb(2)-Co(2) bond lengths. Both Nb(2)-Al(2) bond lengths are 2.93 Å. There is one shorter (2.82 Å) and two longer (2.95 Å) Nb(2)-Al(1) bond lengths. In the fourth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. The Nb(1)-Co(3) bond length is 2.72 Å. Both Nb(1)-Co(1) bond lengths are 3.00 Å. Both Nb(1)-Co(2) bond lengths are 2.73 Å. There are two shorter (2.88 Å) and one longer (2.93 Å) Nb(1)-Al(1) bond length. There are two shorter (2.92 Å) and two longer (2.99 Å) Nb(1)-Al(2) bond lengths. In the fifth Nb site, Nb(1) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), one Co(3), two equivalent Co(1), two equivalent Co(2), three equivalent Al(1), and four equivalent Al(2) atoms. The Nb(1)-Nb(1) bond length is 3.27 Å. The Nb(1)-Co(3) bond length is 2.72 Å. Both Nb(1)-Co(1) bond lengths are 3.00 Å. Both Nb(1)-Co(2) bond lengths are 2.73 Å. There are two shorter (2.88 Å) and one longer (2.93 Å) Nb(1)-Al(1) bond length. There are two shorter (2.92 Å) and two longer (2.99 Å) Nb(1)-Al(2) bond lengths. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to two Nb(2,2); four Nb(1,1); two equivalent Al(1); and four equivalent Al(2) atoms to form distorted CoNb6Al6 cuboctahedra that share corners with two equivalent Co(3)Nb6Al2Co4 cuboctahedra, corners with four equivalent Co(1)Nb6Al6 cuboctahedra, corners with eight equivalent Co(2)Nb6Al2Co4 cuboctahedra, edges with two equivalent Co(1)Nb6Al6 cuboctahedra, edges with four equivalent Co(3)Nb6Al2Co4 cuboctahedra, and faces with four equivalent Co(2)Nb6Al2Co4 cuboctahedra. Both Co(1)-Al(1) bond lengths are 2.46 Å. There are two shorter (2.41 Å) and two longer (2.51 Å) Co(1)-Al(2) bond lengths. In the second Co site, Co(2) is bonded to two Nb(1,1); four Nb(2,2); two equivalent Co(2); two equivalent Co(3); and two equivalent Al(1) atoms to form distorted CoNb6Al2Co4 cuboctahedra that share corners with four equivalent Co(2)Nb6Al2Co4 cuboctahedra, corners with four equivalent Co(1)Nb6Al6 cuboctahedra, edges with two equivalent Co(2)Nb6Al2Co4 cuboctahedra, faces with two equivalent Co(1)Nb6Al6 cuboctahedra, faces with four equivalent Co(2)Nb6Al2Co4 cuboctahedra, and faces with four equivalent Co(3)Nb6Al2Co4 cuboctahedra. There is one shorter (2.41 Å) and one longer (2.62 Å) Co(2)-Co(2) bond length. There is one shorter (2.39 Å) and one longer (2.53 Å) Co(2)-Co(3) bond length. Both Co(2)-Al(1) bond lengths are 2.40 Å. In the third Co site, Co(3) is bonded to two Nb(1,1); four Nb(2,2); four equivalent Co(2); and two equivalent Al(1) atoms to form distorted CoNb6Al2Co4 cuboctahedra that share corners with two equivalent Co(1)Nb6Al6 cuboctahedra, corners with four equivalent Co(3)Nb6Al2Co4 cuboctahedra, edges with two equivalent Co(3)Nb6Al2Co4 cuboctahedra, edges with four equivalent Co(1)Nb6Al6 cuboctahedra, and faces with eight equivalent Co(2)Nb6Al2Co4 cuboctahedra. Both Co(3)-Al(1) bond lengths are 2.43 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 4-coordinate geometry to three Nb(1,1); three equivalent Nb(2); one Co(1); one Co(3); two equivalent Co(2); and two equivalent Al(2) atoms. Both Al(1)-Al(2) bond lengths are 2.59 Å. In the second Al site, Al(2) is bonded in a 12-coordinate geometry to two Nb(2,2); four Nb(1,1,1); two equivalent Co(1); two equivalent Al(1); and two equivalent Al(2) atoms. There is one shorter (2.45 Å) and one longer (2.58 Å) Al(2)-Al(2) bond length.