Fe12N5 crystallizes in the trigonal P-31m space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a bent 120 degrees geometry to one N(1) and one N(2) atom. In the second Fe site, Fe(2) is bonded in a distorted T-shaped geometry to one N(3) and two equivalent N(1) atoms. In the third Fe site, Fe(3) is bonded in a distorted trigonal planar geometry to one N(2) and two equivalent N(1) atoms. There are three inequivalent N sites. In the first N site, N(3) is bonded to six equivalent Fe(2) atoms to form corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second N site, N(1) is bonded to two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms to form a mixture of edge and corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles range from 48-51°. In the third N site, N(2) is bonded to two equivalent Fe(3) and four equivalent Fe(1) atoms to form corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°.
Fe12N5 crystallizes in the trigonal P-31m space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a bent 120 degrees geometry to one N(1) and one N(2) atom. The Fe(1)-N(1) bond length is 1.89 Å. The Fe(1)-N(2) bond length is 1.92 Å. In the second Fe site, Fe(2) is bonded in a distorted T-shaped geometry to one N(3) and two equivalent N(1) atoms. The Fe(2)-N(3) bond length is 1.91 Å. Both Fe(2)-N(1) bond lengths are 1.95 Å. In the third Fe site, Fe(3) is bonded in a distorted trigonal planar geometry to one N(2) and two equivalent N(1) atoms. The Fe(3)-N(2) bond length is 1.89 Å. Both Fe(3)-N(1) bond lengths are 1.90 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded to six equivalent Fe(2) atoms to form corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second N site, N(1) is bonded to two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms to form a mixture of edge and corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles range from 48-51°. In the third N site, N(2) is bonded to two equivalent Fe(3) and four equivalent Fe(1) atoms to form corner-sharing NFe6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°.