CoAl2N3 is Enargite-like structured and crystallizes in the orthorhombic Cmc2_1 space group. Co(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form CoN4 tetrahedra that share corners with two equivalent Co(1)N4 tetrahedra and corners with ten equivalent Al(1)N4 tetrahedra. Al(1) is bonded to one N(2) and three equivalent N(1) atoms to form AlN4 tetrahedra that share corners with five equivalent Co(1)N4 tetrahedra and corners with seven equivalent Al(1)N4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Co(1) and three equivalent Al(1) atoms to form NAl3Co tetrahedra that share corners with five equivalent N(2)Al2Co2 tetrahedra and corners with seven equivalent N(1)Al3Co tetrahedra. In the second N site, N(2) is bonded to two equivalent Co(1) and two equivalent Al(1) atoms to form NAl2Co2 tetrahedra that share corners with two equivalent N(2)Al2Co2 tetrahedra and corners with ten equivalent N(1)Al3Co tetrahedra.
CoAl2N3 is Enargite-like structured and crystallizes in the orthorhombic Cmc2_1 space group. Co(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form CoN4 tetrahedra that share corners with two equivalent Co(1)N4 tetrahedra and corners with ten equivalent Al(1)N4 tetrahedra. Both Co(1)-N(1) bond lengths are 1.97 Å. There is one shorter (1.87 Å) and one longer (1.89 Å) Co(1)-N(2) bond length. Al(1) is bonded to one N(2) and three equivalent N(1) atoms to form AlN4 tetrahedra that share corners with five equivalent Co(1)N4 tetrahedra and corners with seven equivalent Al(1)N4 tetrahedra. The Al(1)-N(2) bond length is 1.92 Å. There are two shorter (1.88 Å) and one longer (1.89 Å) Al(1)-N(1) bond length. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Co(1) and three equivalent Al(1) atoms to form NAl3Co tetrahedra that share corners with five equivalent N(2)Al2Co2 tetrahedra and corners with seven equivalent N(1)Al3Co tetrahedra. In the second N site, N(2) is bonded to two equivalent Co(1) and two equivalent Al(1) atoms to form NAl2Co2 tetrahedra that share corners with two equivalent N(2)Al2Co2 tetrahedra and corners with ten equivalent N(1)Al3Co tetrahedra.