Cr4N2Se3 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 2-coordinate geometry to two equivalent N(1), two equivalent Se(1), and two equivalent Se(2) atoms. In the second Cr site, Cr(2) is bonded in a distorted bent 120 degrees geometry to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms. N(1) is bonded to two equivalent Cr(1) and two equivalent Cr(2) atoms to form NCr4 tetrahedra that share corners with two equivalent N(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids,  an edgeedge with one N(1)Cr4 tetrahedra, and edges with three equivalent Se(2)Cr5 trigonal bipyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cr(2) and four equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(2) atoms to form distorted SeCr5 trigonal bipyramids that share corners with four equivalent N(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, edges with three equivalent N(1)Cr4 tetrahedra, and edges with two equivalent Se(2)Cr5 trigonal bipyramids.
Cr4N2Se3 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 2-coordinate geometry to two equivalent N(1), two equivalent Se(1), and two equivalent Se(2) atoms. There is one shorter (1.92 Å) and one longer (1.97 Å) Cr(1)-N(1) bond length. Both Cr(1)-Se(1) bond lengths are 2.78 Å. Both Cr(1)-Se(2) bond lengths are 2.64 Å. In the second Cr site, Cr(2) is bonded in a distorted bent 120 degrees geometry to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms. Both Cr(2)-N(1) bond lengths are 1.96 Å. The Cr(2)-Se(1) bond length is 2.69 Å. There is one shorter (2.53 Å) and two longer (2.65 Å) Cr(2)-Se(2) bond lengths. N(1) is bonded to two equivalent Cr(1) and two equivalent Cr(2) atoms to form NCr4 tetrahedra that share corners with two equivalent N(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids,  an edgeedge with one N(1)Cr4 tetrahedra, and edges with three equivalent Se(2)Cr5 trigonal bipyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cr(2) and four equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(2) atoms to form distorted SeCr5 trigonal bipyramids that share corners with four equivalent N(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, edges with three equivalent N(1)Cr4 tetrahedra, and edges with two equivalent Se(2)Cr5 trigonal bipyramids.