Y2AlN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to two equivalent N(1), two equivalent N(3), and three equivalent N(2) atoms. In the second Y site, Y(2) is bonded to two equivalent N(2), two equivalent N(3), and three equivalent N(1) atoms to form distorted YN7 pentagonal bipyramids that share corners with four equivalent Y(2)N7 pentagonal bipyramids,  a cornercorner with one Al(1)N4 tetrahedra, edges with three equivalent Y(2)N7 pentagonal bipyramids, and edges with four equivalent Al(1)N4 tetrahedra. Al(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form AlN4 tetrahedra that share  a cornercorner with one Y(2)N7 pentagonal bipyramid, corners with two equivalent Al(1)N4 tetrahedra, and edges with four equivalent Y(2)N7 pentagonal bipyramids. There are three inequivalent N sites. In the first N site, N(3) is bonded in a 6-coordinate geometry to two equivalent Y(1), two equivalent Y(2), and two equivalent Al(1) atoms. In the second N site, N(1) is bonded in a 6-coordinate geometry to two equivalent Y(1), three equivalent Y(2), and one Al(1) atom. In the third N site, N(2) is bonded to two equivalent Y(2), three equivalent Y(1), and one Al(1) atom to form a mixture of distorted corner and edge-sharing NY5Al octahedra. The corner-sharing octahedral tilt angles are 20°.
Y2AlN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to two equivalent N(1), two equivalent N(3), and three equivalent N(2) atoms. There is one shorter (2.30 Å) and one longer (2.40 Å) Y(1)-N(1) bond length. Both Y(1)-N(3) bond lengths are 2.82 Å. There is one shorter (2.41 Å) and two longer (2.81 Å) Y(1)-N(2) bond lengths. In the second Y site, Y(2) is bonded to two equivalent N(2), two equivalent N(3), and three equivalent N(1) atoms to form distorted YN7 pentagonal bipyramids that share corners with four equivalent Y(2)N7 pentagonal bipyramids,  a cornercorner with one Al(1)N4 tetrahedra, edges with three equivalent Y(2)N7 pentagonal bipyramids, and edges with four equivalent Al(1)N4 tetrahedra. There is one shorter (2.37 Å) and one longer (2.51 Å) Y(2)-N(2) bond length. Both Y(2)-N(3) bond lengths are 2.41 Å. There is one shorter (2.43 Å) and two longer (2.84 Å) Y(2)-N(1) bond lengths. Al(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form AlN4 tetrahedra that share  a cornercorner with one Y(2)N7 pentagonal bipyramid, corners with two equivalent Al(1)N4 tetrahedra, and edges with four equivalent Y(2)N7 pentagonal bipyramids. The Al(1)-N(1) bond length is 1.91 Å. The Al(1)-N(2) bond length is 1.89 Å. Both Al(1)-N(3) bond lengths are 1.85 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded in a 6-coordinate geometry to two equivalent Y(1), two equivalent Y(2), and two equivalent Al(1) atoms. In the second N site, N(1) is bonded in a 6-coordinate geometry to two equivalent Y(1), three equivalent Y(2), and one Al(1) atom. In the third N site, N(2) is bonded to two equivalent Y(2), three equivalent Y(1), and one Al(1) atom to form a mixture of distorted corner and edge-sharing NY5Al octahedra. The corner-sharing octahedral tilt angles are 20°.