Mg8Fe3N8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing MgN5 square pyramids. In the second Mg site, Mg(2) is bonded in a distorted rectangular see-saw-like geometry to one N(3), one N(4), and two equivalent N(2) atoms. In the third Mg site, Mg(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing MgN5 trigonal bipyramids. In the fourth Mg site, Mg(4) is bonded to one N(1), one N(2), and three equivalent N(3) atoms to form a mixture of distorted edge and corner-sharing MgN5 trigonal bipyramids. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a linear geometry to two equivalent N(4) atoms. In the second Fe site, Fe(2) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(3) atom. There are four inequivalent N sites. In the first N site, N(1) is bonded to one Mg(4), two equivalent Mg(1), two equivalent Mg(3), and one Fe(2) atom to form a mixture of distorted edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles are 12°. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), and one Fe(2) atom. In the third N site, N(3) is bonded to one Mg(2), one Mg(3), three equivalent Mg(4), and one Fe(2) atom to form a mixture of distorted edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles range from 12-63°. In the fourth N site, N(4) is bonded to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), and one Fe(1) atom to form a mixture of edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-63°.
Mg8Fe3N8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing MgN5 square pyramids. The Mg(1)-N(2) bond length is 2.41 Å. There is one shorter (2.28 Å) and one longer (2.32 Å) Mg(1)-N(1) bond length. Both Mg(1)-N(4) bond lengths are 2.18 Å. In the second Mg site, Mg(2) is bonded in a distorted rectangular see-saw-like geometry to one N(3), one N(4), and two equivalent N(2) atoms. The Mg(2)-N(3) bond length is 2.23 Å. The Mg(2)-N(4) bond length is 2.21 Å. Both Mg(2)-N(2) bond lengths are 2.19 Å. In the third Mg site, Mg(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing MgN5 trigonal bipyramids. The Mg(3)-N(3) bond length is 2.46 Å. Both Mg(3)-N(1) bond lengths are 2.19 Å. There is one shorter (2.14 Å) and one longer (2.31 Å) Mg(3)-N(4) bond length. In the fourth Mg site, Mg(4) is bonded to one N(1), one N(2), and three equivalent N(3) atoms to form a mixture of distorted edge and corner-sharing MgN5 trigonal bipyramids. The Mg(4)-N(1) bond length is 2.20 Å. The Mg(4)-N(2) bond length is 2.19 Å. There are two shorter (2.19 Å) and one longer (2.52 Å) Mg(4)-N(3) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a linear geometry to two equivalent N(4) atoms. Both Fe(1)-N(4) bond lengths are 1.83 Å. In the second Fe site, Fe(2) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(3) atom. The Fe(2)-N(1) bond length is 1.78 Å. The Fe(2)-N(2) bond length is 1.74 Å. The Fe(2)-N(3) bond length is 1.76 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded to one Mg(4), two equivalent Mg(1), two equivalent Mg(3), and one Fe(2) atom to form a mixture of distorted edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles are 12°. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), and one Fe(2) atom. In the third N site, N(3) is bonded to one Mg(2), one Mg(3), three equivalent Mg(4), and one Fe(2) atom to form a mixture of distorted edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles range from 12-63°. In the fourth N site, N(4) is bonded to one Mg(2), two equivalent Mg(1), two equivalent Mg(3), and one Fe(1) atom to form a mixture of edge and corner-sharing NMg5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-63°.