YAl2N3 crystallizes in the orthorhombic Cmc2_1 space group. Y(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form distorted YN5 trigonal bipyramids that share corners with eight equivalent Al(1)N4 tetrahedra, corners with two equivalent Y(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N4 tetrahedra, and edges with two equivalent Y(1)N5 trigonal bipyramids. Al(1) is bonded to one N(2) and three equivalent N(1) atoms to form AlN4 tetrahedra that share corners with seven equivalent Al(1)N4 tetrahedra, corners with four equivalent Y(1)N5 trigonal bipyramids, and  an edgeedge with one Y(1)N5 trigonal bipyramid. There are two inequivalent N sites. In the first N site, N(2) is bonded to three equivalent Y(1) and two equivalent Al(1) atoms to form distorted NY3Al2 trigonal bipyramids that share corners with eight equivalent N(1)YAl3 tetrahedra, corners with two equivalent N(2)Y3Al2 trigonal bipyramids, edges with two equivalent N(1)YAl3 tetrahedra, and edges with two equivalent N(2)Y3Al2 trigonal bipyramids. In the second N site, N(1) is bonded to one Y(1) and three equivalent Al(1) atoms to form NYAl3 tetrahedra that share corners with seven equivalent N(1)YAl3 tetrahedra, corners with four equivalent N(2)Y3Al2 trigonal bipyramids, and  an edgeedge with one N(2)Y3Al2 trigonal bipyramid.
YAl2N3 crystallizes in the orthorhombic Cmc2_1 space group. Y(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form distorted YN5 trigonal bipyramids that share corners with eight equivalent Al(1)N4 tetrahedra, corners with two equivalent Y(1)N5 trigonal bipyramids, edges with two equivalent Al(1)N4 tetrahedra, and edges with two equivalent Y(1)N5 trigonal bipyramids. Both Y(1)-N(1) bond lengths are 2.28 Å. There are a spread of Y(1)-N(2) bond distances ranging from 2.33-2.75 Å. Al(1) is bonded to one N(2) and three equivalent N(1) atoms to form AlN4 tetrahedra that share corners with seven equivalent Al(1)N4 tetrahedra, corners with four equivalent Y(1)N5 trigonal bipyramids, and  an edgeedge with one Y(1)N5 trigonal bipyramid. The Al(1)-N(2) bond length is 1.95 Å. There is one shorter (1.89 Å) and two longer (1.90 Å) Al(1)-N(1) bond lengths. There are two inequivalent N sites. In the first N site, N(2) is bonded to three equivalent Y(1) and two equivalent Al(1) atoms to form distorted NY3Al2 trigonal bipyramids that share corners with eight equivalent N(1)YAl3 tetrahedra, corners with two equivalent N(2)Y3Al2 trigonal bipyramids, edges with two equivalent N(1)YAl3 tetrahedra, and edges with two equivalent N(2)Y3Al2 trigonal bipyramids. In the second N site, N(1) is bonded to one Y(1) and three equivalent Al(1) atoms to form NYAl3 tetrahedra that share corners with seven equivalent N(1)YAl3 tetrahedra, corners with four equivalent N(2)Y3Al2 trigonal bipyramids, and  an edgeedge with one N(2)Y3Al2 trigonal bipyramid.