GaAl2N3 is Chalcopyrite-like structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one N(1), one N(6), and two equivalent N(4) atoms to form GaN4 tetrahedra that share  a cornercorner with one Al(3)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, and corners with three equivalent Al(4)N4 tetrahedra. In the second Ga site, Ga(2) is bonded to one N(2), one N(4), and two equivalent N(5) atoms to form GaN4 tetrahedra that share  a cornercorner with one Al(4)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, and corners with three equivalent Al(2)N4 tetrahedra. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one N(3), one N(5), and two equivalent N(6) atoms to form AlN4 tetrahedra that share  a cornercorner with one Al(2)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Al(3)N4 tetrahedra. In the second Al site, Al(2) is bonded to one N(3), one N(4), and two equivalent N(2) atoms to form AlN4 tetrahedra that share  a cornercorner with one Al(1)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Ga(2)N4 tetrahedra. In the third Al site, Al(3) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form AlN4 tetrahedra that share  a cornercorner with one Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Al(1)N4 tetrahedra. In the fourth Al site, Al(4) is bonded to one N(2), one N(6), and two equivalent N(1) atoms to form AlN4 tetrahedra that share  a cornercorner with one Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Ga(1)N4 tetrahedra. There are six inequivalent N sites. In the first N site, N(1) is bonded to one Ga(1), one Al(3), and two equivalent Al(4) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(6)Al3Ga tetrahedra. In the second N site, N(2) is bonded to one Ga(2), one Al(4), and two equivalent Al(2) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(6)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, and corners with three equivalent N(4)AlGa3 tetrahedra. In the third N site, N(3) is bonded to one Al(1), one Al(2), and two equivalent Al(3) atoms to form NAl4 tetrahedra that share  a cornercorner with one N(4)AlGa3 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, and corners with three equivalent N(5)Al2Ga2 tetrahedra. In the fourth N site, N(4) is bonded to one Ga(2), two equivalent Ga(1), and one Al(2) atom to form NAlGa3 tetrahedra that share  a cornercorner with one N(3)Al4 tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(2)Al3Ga tetrahedra. In the fifth N site, N(5) is bonded to two equivalent Ga(2), one Al(1), and one Al(3) atom to form NAl2Ga2 tetrahedra that share  a cornercorner with one N(1)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(3)Al4 tetrahedra. In the sixth N site, N(6) is bonded to one Ga(1), one Al(4), and two equivalent Al(1) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(2)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(1)Al3Ga tetrahedra.
GaAl2N3 is Chalcopyrite-like structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one N(1), one N(6), and two equivalent N(4) atoms to form GaN4 tetrahedra that share  a cornercorner with one Al(3)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, and corners with three equivalent Al(4)N4 tetrahedra. The Ga(1)-N(1) bond length is 1.96 Å. The Ga(1)-N(6) bond length is 1.95 Å. Both Ga(1)-N(4) bond lengths are 1.93 Å. In the second Ga site, Ga(2) is bonded to one N(2), one N(4), and two equivalent N(5) atoms to form GaN4 tetrahedra that share  a cornercorner with one Al(4)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, and corners with three equivalent Al(2)N4 tetrahedra. The Ga(2)-N(2) bond length is 1.96 Å. The Ga(2)-N(4) bond length is 1.93 Å. Both Ga(2)-N(5) bond lengths are 1.94 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one N(3), one N(5), and two equivalent N(6) atoms to form AlN4 tetrahedra that share  a cornercorner with one Al(2)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Al(3)N4 tetrahedra. The Al(1)-N(3) bond length is 1.91 Å. The Al(1)-N(5) bond length is 1.88 Å. Both Al(1)-N(6) bond lengths are 1.89 Å. In the second Al site, Al(2) is bonded to one N(3), one N(4), and two equivalent N(2) atoms to form AlN4 tetrahedra that share  a cornercorner with one Al(1)N4 tetrahedra, corners with two equivalent Ga(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Ga(2)N4 tetrahedra. The Al(2)-N(3) bond length is 1.90 Å. The Al(2)-N(4) bond length is 1.89 Å. Both Al(2)-N(2) bond lengths are 1.89 Å. In the third Al site, Al(3) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form AlN4 tetrahedra that share  a cornercorner with one Ga(1)N4 tetrahedra, corners with two equivalent Ga(2)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Al(1)N4 tetrahedra. The Al(3)-N(1) bond length is 1.90 Å. The Al(3)-N(5) bond length is 1.90 Å. Both Al(3)-N(3) bond lengths are 1.91 Å. In the fourth Al site, Al(4) is bonded to one N(2), one N(6), and two equivalent N(1) atoms to form AlN4 tetrahedra that share  a cornercorner with one Ga(2)N4 tetrahedra, corners with two equivalent Al(1)N4 tetrahedra, corners with two equivalent Al(2)N4 tetrahedra, corners with two equivalent Al(3)N4 tetrahedra, corners with two equivalent Al(4)N4 tetrahedra, and corners with three equivalent Ga(1)N4 tetrahedra. The Al(4)-N(2) bond length is 1.90 Å. The Al(4)-N(6) bond length is 1.90 Å. Both Al(4)-N(1) bond lengths are 1.90 Å. There are six inequivalent N sites. In the first N site, N(1) is bonded to one Ga(1), one Al(3), and two equivalent Al(4) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(6)Al3Ga tetrahedra. In the second N site, N(2) is bonded to one Ga(2), one Al(4), and two equivalent Al(2) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(6)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, and corners with three equivalent N(4)AlGa3 tetrahedra. In the third N site, N(3) is bonded to one Al(1), one Al(2), and two equivalent Al(3) atoms to form NAl4 tetrahedra that share  a cornercorner with one N(4)AlGa3 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, and corners with three equivalent N(5)Al2Ga2 tetrahedra. In the fourth N site, N(4) is bonded to one Ga(2), two equivalent Ga(1), and one Al(2) atom to form NAlGa3 tetrahedra that share  a cornercorner with one N(3)Al4 tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(1)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(2)Al3Ga tetrahedra. In the fifth N site, N(5) is bonded to two equivalent Ga(2), one Al(1), and one Al(3) atom to form NAl2Ga2 tetrahedra that share  a cornercorner with one N(1)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(2)Al3Ga tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(3)Al4 tetrahedra. In the sixth N site, N(6) is bonded to one Ga(1), one Al(4), and two equivalent Al(1) atoms to form NAl3Ga tetrahedra that share  a cornercorner with one N(2)Al3Ga tetrahedra, corners with two equivalent N(5)Al2Ga2 tetrahedra, corners with two equivalent N(6)Al3Ga tetrahedra, corners with two equivalent N(3)Al4 tetrahedra, corners with two equivalent N(4)AlGa3 tetrahedra, and corners with three equivalent N(1)Al3Ga tetrahedra.