Zn3Al2N4 crystallizes in the monoclinic C2/c space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent N(1) and two equivalent N(2) atoms. In the second Zn site, Zn(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted ZnN4 tetrahedra that share corners with eight equivalent Al(1)N4 tetrahedra. Al(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form AlN4 tetrahedra that share corners with two equivalent Al(1)N4 tetrahedra, corners with four equivalent Zn(2)N4 tetrahedra, and  an edgeedge with one Al(1)N4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Zn(2), two equivalent Zn(1), and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing NAl2Zn3 trigonal bipyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Zn(2), two equivalent Zn(1), and two equivalent Al(1) atoms.
Zn3Al2N4 crystallizes in the monoclinic C2/c space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent N(1) and two equivalent N(2) atoms. There is one shorter (1.97 Å) and one longer (2.18 Å) Zn(1)-N(1) bond length. There is one shorter (1.99 Å) and one longer (2.47 Å) Zn(1)-N(2) bond length. In the second Zn site, Zn(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted ZnN4 tetrahedra that share corners with eight equivalent Al(1)N4 tetrahedra. Both Zn(2)-N(1) bond lengths are 2.12 Å. Both Zn(2)-N(2) bond lengths are 2.22 Å. Al(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form AlN4 tetrahedra that share corners with two equivalent Al(1)N4 tetrahedra, corners with four equivalent Zn(2)N4 tetrahedra, and  an edgeedge with one Al(1)N4 tetrahedra. There is one shorter (1.90 Å) and one longer (1.97 Å) Al(1)-N(1) bond length. There is one shorter (1.89 Å) and one longer (1.93 Å) Al(1)-N(2) bond length. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Zn(2), two equivalent Zn(1), and two equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing NAl2Zn3 trigonal bipyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Zn(2), two equivalent Zn(1), and two equivalent Al(1) atoms.