Zr3AlN4 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one N(2), one N(3), and four equivalent N(1) atoms to form ZrN6 octahedra that share corners with six equivalent Zr(1)N6 octahedra, edges with four equivalent Zr(1)N6 octahedra, edges with four equivalent Zr(2)N6 octahedra, and edges with four equivalent Al(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second Zr site, Zr(2) is bonded to two equivalent N(1) and four equivalent N(3) atoms to form ZrN6 octahedra that share corners with two equivalent Al(1)N6 octahedra, corners with four equivalent Zr(2)N6 octahedra, edges with four equivalent Zr(2)N6 octahedra, and edges with eight equivalent Zr(1)N6 octahedra. The corner-sharing octahedra are not tilted. Al(1) is bonded to two equivalent N(1) and four equivalent N(2) atoms to form AlN6 octahedra that share corners with two equivalent Zr(2)N6 octahedra, corners with four equivalent Al(1)N6 octahedra, edges with four equivalent Al(1)N6 octahedra, and edges with eight equivalent Zr(1)N6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Zr(2), four equivalent Zr(1), and one Al(1) atom to form NZr5Al octahedra that share corners with six equivalent N(1)Zr5Al octahedra, edges with four equivalent N(2)Zr2Al4 octahedra, edges with four equivalent N(1)Zr5Al octahedra, and edges with four equivalent N(3)Zr6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second N site, N(2) is bonded to two equivalent Zr(1) and four equivalent Al(1) atoms to form NZr2Al4 octahedra that share corners with two equivalent N(3)Zr6 octahedra, corners with four equivalent N(2)Zr2Al4 octahedra, edges with four equivalent N(2)Zr2Al4 octahedra, and edges with eight equivalent N(1)Zr5Al octahedra. The corner-sharing octahedra are not tilted. In the third N site, N(3) is bonded to two equivalent Zr(1) and four equivalent Zr(2) atoms to form NZr6 octahedra that share corners with two equivalent N(2)Zr2Al4 octahedra, corners with four equivalent N(3)Zr6 octahedra, edges with four equivalent N(3)Zr6 octahedra, and edges with eight equivalent N(1)Zr5Al octahedra. The corner-sharing octahedra are not tilted.
Zr3AlN4 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one N(2), one N(3), and four equivalent N(1) atoms to form ZrN6 octahedra that share corners with six equivalent Zr(1)N6 octahedra, edges with four equivalent Zr(1)N6 octahedra, edges with four equivalent Zr(2)N6 octahedra, and edges with four equivalent Al(1)N6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. The Zr(1)-N(2) bond length is 2.23 Å. The Zr(1)-N(3) bond length is 2.26 Å. All Zr(1)-N(1) bond lengths are 2.28 Å. In the second Zr site, Zr(2) is bonded to two equivalent N(1) and four equivalent N(3) atoms to form ZrN6 octahedra that share corners with two equivalent Al(1)N6 octahedra, corners with four equivalent Zr(2)N6 octahedra, edges with four equivalent Zr(2)N6 octahedra, and edges with eight equivalent Zr(1)N6 octahedra. The corner-sharing octahedra are not tilted. Both Zr(2)-N(1) bond lengths are 2.47 Å. All Zr(2)-N(3) bond lengths are 2.27 Å. Al(1) is bonded to two equivalent N(1) and four equivalent N(2) atoms to form AlN6 octahedra that share corners with two equivalent Zr(2)N6 octahedra, corners with four equivalent Al(1)N6 octahedra, edges with four equivalent Al(1)N6 octahedra, and edges with eight equivalent Zr(1)N6 octahedra. The corner-sharing octahedra are not tilted. Both Al(1)-N(1) bond lengths are 2.02 Å. All Al(1)-N(2) bond lengths are 2.27 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Zr(2), four equivalent Zr(1), and one Al(1) atom to form NZr5Al octahedra that share corners with six equivalent N(1)Zr5Al octahedra, edges with four equivalent N(2)Zr2Al4 octahedra, edges with four equivalent N(1)Zr5Al octahedra, and edges with four equivalent N(3)Zr6 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second N site, N(2) is bonded to two equivalent Zr(1) and four equivalent Al(1) atoms to form NZr2Al4 octahedra that share corners with two equivalent N(3)Zr6 octahedra, corners with four equivalent N(2)Zr2Al4 octahedra, edges with four equivalent N(2)Zr2Al4 octahedra, and edges with eight equivalent N(1)Zr5Al octahedra. The corner-sharing octahedra are not tilted. In the third N site, N(3) is bonded to two equivalent Zr(1) and four equivalent Zr(2) atoms to form NZr6 octahedra that share corners with two equivalent N(2)Zr2Al4 octahedra, corners with four equivalent N(3)Zr6 octahedra, edges with four equivalent N(3)Zr6 octahedra, and edges with eight equivalent N(1)Zr5Al octahedra. The corner-sharing octahedra are not tilted.