Cr4N2Se3 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted L-shaped geometry to two equivalent N(1) and four equivalent Se(2) atoms. In the second Cr site, Cr(2) is bonded to two equivalent N(1) and two equivalent Se(1) atoms to form distorted CrSe2N2 tetrahedra that share corners with eight equivalent Cr(3)Se4N2 octahedra and corners with two equivalent Cr(2)Se2N2 tetrahedra. The corner-sharing octahedral tilt angles range from 52-82°. In the third Cr site, Cr(3) is bonded to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms to form distorted CrSe4N2 octahedra that share corners with five equivalent Cr(3)Se4N2 octahedra, corners with four equivalent Cr(2)Se2N2 tetrahedra, and edges with two equivalent Cr(3)Se4N2 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. N(1) is bonded to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms to form distorted NCr4 trigonal pyramids that share corners with four equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, edges with two equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Cr(2) and two equivalent Cr(3) atoms to form distorted SeCr4 tetrahedra that share corners with two equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, and corners with eight equivalent N(1)Cr4 trigonal pyramids. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(3) atoms to form distorted SeCr5 trigonal bipyramids that share corners with three equivalent Se(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, corners with six equivalent N(1)Cr4 trigonal pyramids, edges with four equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids.
Cr4N2Se3 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted L-shaped geometry to two equivalent N(1) and four equivalent Se(2) atoms. Both Cr(1)-N(1) bond lengths are 2.01 Å. There are two shorter (2.76 Å) and two longer (2.79 Å) Cr(1)-Se(2) bond lengths. In the second Cr site, Cr(2) is bonded to two equivalent N(1) and two equivalent Se(1) atoms to form distorted CrSe2N2 tetrahedra that share corners with eight equivalent Cr(3)Se4N2 octahedra and corners with two equivalent Cr(2)Se2N2 tetrahedra. The corner-sharing octahedral tilt angles range from 52-82°. Both Cr(2)-N(1) bond lengths are 1.83 Å. There is one shorter (2.43 Å) and one longer (2.50 Å) Cr(2)-Se(1) bond length. In the third Cr site, Cr(3) is bonded to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms to form distorted CrSe4N2 octahedra that share corners with five equivalent Cr(3)Se4N2 octahedra, corners with four equivalent Cr(2)Se2N2 tetrahedra, and edges with two equivalent Cr(3)Se4N2 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. There is one shorter (1.95 Å) and one longer (1.98 Å) Cr(3)-N(1) bond length. The Cr(3)-Se(1) bond length is 2.65 Å. There are two shorter (2.64 Å) and one longer (2.67 Å) Cr(3)-Se(2) bond length. N(1) is bonded to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms to form distorted NCr4 trigonal pyramids that share corners with four equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, edges with two equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Cr(2) and two equivalent Cr(3) atoms to form distorted SeCr4 tetrahedra that share corners with two equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, and corners with eight equivalent N(1)Cr4 trigonal pyramids. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(3) atoms to form distorted SeCr5 trigonal bipyramids that share corners with three equivalent Se(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, corners with six equivalent N(1)Cr4 trigonal pyramids, edges with four equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids.