CoFeSe2 crystallizes in the trigonal P-3m1 space group. Fe(1) is bonded to six equivalent Se(1) atoms to form distorted FeSe6 octahedra that share corners with twelve equivalent Co(1)Se6 octahedra, edges with six equivalent Fe(1)Se6 octahedra, and faces with two equivalent Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 50°. Co(1) is bonded to six equivalent Se(1) atoms to form distorted CoSe6 octahedra that share corners with twelve equivalent Fe(1)Se6 octahedra, edges with six equivalent Co(1)Se6 octahedra, and faces with two equivalent Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 50°. Se(1) is bonded in a 6-coordinate geometry to three equivalent Fe(1) and three equivalent Co(1) atoms.
CoFeSe2 crystallizes in the trigonal P-3m1 space group. Fe(1) is bonded to six equivalent Se(1) atoms to form distorted FeSe6 octahedra that share corners with twelve equivalent Co(1)Se6 octahedra, edges with six equivalent Fe(1)Se6 octahedra, and faces with two equivalent Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 50°. All Fe(1)-Se(1) bond lengths are 2.44 Å. Co(1) is bonded to six equivalent Se(1) atoms to form distorted CoSe6 octahedra that share corners with twelve equivalent Fe(1)Se6 octahedra, edges with six equivalent Co(1)Se6 octahedra, and faces with two equivalent Fe(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 50°. All Co(1)-Se(1) bond lengths are 2.45 Å. Se(1) is bonded in a 6-coordinate geometry to three equivalent Fe(1) and three equivalent Co(1) atoms.