Ti4(NbAl3)3 is alpha La-derived structured and crystallizes in the tetragonal P4/mmm space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to four equivalent Nb(2) and eight equivalent Al(2) atoms to form TiNb4Al8 cuboctahedra that share corners with four equivalent Ti(1)Nb4Al8 cuboctahedra, corners with eight equivalent Nb(1)Ti4Al8 cuboctahedra, edges with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Al(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. In the second Ti site, Ti(2) is bonded to four equivalent Nb(2) and eight equivalent Al(2) atoms to form TiNb4Al8 cuboctahedra that share corners with four equivalent Ti(2)Nb4Al8 cuboctahedra, corners with eight equivalent Al(1)Ti4Al8 cuboctahedra, edges with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Nb(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(1)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. In the third Ti site, Ti(3) is bonded to two equivalent Nb(1), two equivalent Al(1), and eight equivalent Al(2) atoms to form TiNb2Al10 cuboctahedra that share corners with four equivalent Ti(3)Nb2Al10 cuboctahedra, corners with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with four equivalent Ti(1)Nb4Al8 cuboctahedra, edges with four equivalent Ti(2)Nb4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Nb(1)Ti4Al8 cuboctahedra, faces with two equivalent Nb(2)Ti4Al8 cuboctahedra, faces with two equivalent Al(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Ti(3) and eight equivalent Al(2) atoms to form NbTi4Al8 cuboctahedra that share corners with four equivalent Nb(1)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(1)Nb4Al8 cuboctahedra, edges with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, faces with four equivalent Al(1)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. In the second Nb site, Nb(2) is bonded to two equivalent Ti(1), two equivalent Ti(2), and eight equivalent Al(2) atoms to form NbTi4Al8 cuboctahedra that share corners with four equivalent Nb(2)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with four equivalent Nb(1)Ti4Al8 cuboctahedra, edges with four equivalent Al(1)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(3)Nb2Al10 cuboctahedra, faces with two equivalent Ti(1)Nb4Al8 cuboctahedra, faces with two equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Ti(3) and eight equivalent Al(2) atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent Al(1)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(2)Nb4Al8 cuboctahedra, edges with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(1)Nb4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, faces with four equivalent Nb(1)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. In the second Al site, Al(2) is bonded to one Ti(1), one Ti(2), two equivalent Ti(3), one Nb(1), two equivalent Nb(2), one Al(1), and four equivalent Al(2) atoms to form AlTi4Nb3Al5 cuboctahedra that share corners with twelve equivalent Al(2)Ti4Nb3Al5 cuboctahedra, edges with two equivalent Ti(1)Nb4Al8 cuboctahedra, edges with two equivalent Ti(2)Nb4Al8 cuboctahedra, edges with two equivalent Nb(1)Ti4Al8 cuboctahedra, edges with two equivalent Al(1)Ti4Al8 cuboctahedra, edges with four equivalent Ti(3)Nb2Al10 cuboctahedra, edges with four equivalent Nb(2)Ti4Al8 cuboctahedra, edges with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra,  a faceface with one Ti(1)Nb4Al8 cuboctahedra,  a faceface with one Ti(2)Nb4Al8 cuboctahedra,  a faceface with one Nb(1)Ti4Al8 cuboctahedra,  a faceface with one Al(1)Ti4Al8 cuboctahedra, faces with two equivalent Ti(3)Nb2Al10 cuboctahedra, faces with two equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with ten equivalent Al(2)Ti4Nb3Al5 cuboctahedra.
Ti4(NbAl3)3 is alpha La-derived structured and crystallizes in the tetragonal P4/mmm space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to four equivalent Nb(2) and eight equivalent Al(2) atoms to form TiNb4Al8 cuboctahedra that share corners with four equivalent Ti(1)Nb4Al8 cuboctahedra, corners with eight equivalent Nb(1)Ti4Al8 cuboctahedra, edges with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Al(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. All Ti(1)-Nb(2) bond lengths are 2.84 Å. All Ti(1)-Al(2) bond lengths are 2.87 Å. In the second Ti site, Ti(2) is bonded to four equivalent Nb(2) and eight equivalent Al(2) atoms to form TiNb4Al8 cuboctahedra that share corners with four equivalent Ti(2)Nb4Al8 cuboctahedra, corners with eight equivalent Al(1)Ti4Al8 cuboctahedra, edges with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Nb(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(1)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. All Ti(2)-Nb(2) bond lengths are 2.84 Å. All Ti(2)-Al(2) bond lengths are 2.86 Å. In the third Ti site, Ti(3) is bonded to two equivalent Nb(1), two equivalent Al(1), and eight equivalent Al(2) atoms to form TiNb2Al10 cuboctahedra that share corners with four equivalent Ti(3)Nb2Al10 cuboctahedra, corners with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with four equivalent Ti(1)Nb4Al8 cuboctahedra, edges with four equivalent Ti(2)Nb4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Nb(1)Ti4Al8 cuboctahedra, faces with two equivalent Nb(2)Ti4Al8 cuboctahedra, faces with two equivalent Al(1)Ti4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. Both Ti(3)-Nb(1) bond lengths are 2.84 Å. Both Ti(3)-Al(1) bond lengths are 2.84 Å. All Ti(3)-Al(2) bond lengths are 2.86 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Ti(3) and eight equivalent Al(2) atoms to form NbTi4Al8 cuboctahedra that share corners with four equivalent Nb(1)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(1)Nb4Al8 cuboctahedra, edges with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, faces with four equivalent Al(1)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. All Nb(1)-Al(2) bond lengths are 2.86 Å. In the second Nb site, Nb(2) is bonded to two equivalent Ti(1), two equivalent Ti(2), and eight equivalent Al(2) atoms to form NbTi4Al8 cuboctahedra that share corners with four equivalent Nb(2)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(3)Nb2Al10 cuboctahedra, edges with four equivalent Nb(1)Ti4Al8 cuboctahedra, edges with four equivalent Al(1)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(3)Nb2Al10 cuboctahedra, faces with two equivalent Ti(1)Nb4Al8 cuboctahedra, faces with two equivalent Ti(2)Nb4Al8 cuboctahedra, faces with four equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. All Nb(2)-Al(2) bond lengths are 2.86 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Ti(3) and eight equivalent Al(2) atoms to form AlTi4Al8 cuboctahedra that share corners with four equivalent Al(1)Ti4Al8 cuboctahedra, corners with eight equivalent Ti(2)Nb4Al8 cuboctahedra, edges with eight equivalent Nb(2)Ti4Al8 cuboctahedra, edges with sixteen equivalent Al(2)Ti4Nb3Al5 cuboctahedra, faces with two equivalent Ti(1)Nb4Al8 cuboctahedra, faces with four equivalent Ti(3)Nb2Al10 cuboctahedra, faces with four equivalent Nb(1)Ti4Al8 cuboctahedra, and faces with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra. All Al(1)-Al(2) bond lengths are 2.87 Å. In the second Al site, Al(2) is bonded to one Ti(1), one Ti(2), two equivalent Ti(3), one Nb(1), two equivalent Nb(2), one Al(1), and four equivalent Al(2) atoms to form AlTi4Nb3Al5 cuboctahedra that share corners with twelve equivalent Al(2)Ti4Nb3Al5 cuboctahedra, edges with two equivalent Ti(1)Nb4Al8 cuboctahedra, edges with two equivalent Ti(2)Nb4Al8 cuboctahedra, edges with two equivalent Nb(1)Ti4Al8 cuboctahedra, edges with two equivalent Al(1)Ti4Al8 cuboctahedra, edges with four equivalent Ti(3)Nb2Al10 cuboctahedra, edges with four equivalent Nb(2)Ti4Al8 cuboctahedra, edges with eight equivalent Al(2)Ti4Nb3Al5 cuboctahedra,  a faceface with one Ti(1)Nb4Al8 cuboctahedra,  a faceface with one Ti(2)Nb4Al8 cuboctahedra,  a faceface with one Nb(1)Ti4Al8 cuboctahedra,  a faceface with one Al(1)Ti4Al8 cuboctahedra, faces with two equivalent Ti(3)Nb2Al10 cuboctahedra, faces with two equivalent Nb(2)Ti4Al8 cuboctahedra, and faces with ten equivalent Al(2)Ti4Nb3Al5 cuboctahedra. There are two shorter (2.83 Å) and two longer (2.85 Å) Al(2)-Al(2) bond lengths.