Ca8Fe3N8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 square pyramids. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to one N(3), one N(4), and three equivalent N(2) atoms. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. In the fourth Ca site, Ca(4) is bonded to one N(1), one N(2), and three equivalent N(3) atoms to form a mixture of distorted corner and edge-sharing CaN5 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 Ca(4), two equivalent Ca(1), two equivalent Ca(3), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-50°. In the second N site, N(2) is bonded to one Ca(1), one Ca(4), three equivalent Ca(2), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-50°. In the third N site, N(3) is bonded to one Ca(2), one Ca(3), three equivalent Ca(4), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 16-63°. In the fourth N site, N(4) is bonded to one Ca(2), two equivalent Ca(1), two equivalent Ca(3), and one Fe(1) atom to form a mixture of corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-63°.
Ca8Fe3N8 crystallizes in the monoclinic C2/m space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 square pyramids. The Ca(1)-N(2) bond length is 2.61 Å. There is one shorter (2.53 Å) and one longer (2.59 Å) Ca(1)-N(1) bond length. Both Ca(1)-N(4) bond lengths are 2.50 Å. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to one N(3), one N(4), and three equivalent N(2) atoms. The Ca(2)-N(3) bond length is 2.49 Å. The Ca(2)-N(4) bond length is 2.46 Å. There are two shorter (2.52 Å) and one longer (2.69 Å) Ca(2)-N(2) bond length. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. The Ca(3)-N(3) bond length is 2.69 Å. Both Ca(3)-N(1) bond lengths are 2.52 Å. There is one shorter (2.36 Å) and one longer (2.72 Å) Ca(3)-N(4) bond length. In the fourth Ca site, Ca(4) is bonded to one N(1), one N(2), and three equivalent N(3) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. The Ca(4)-N(1) bond length is 2.48 Å. The Ca(4)-N(2) bond length is 2.52 Å. There are two shorter (2.53 Å) and one longer (2.57 Å) Ca(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 1.85 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 1.76 Å. The Fe(2)-N(2) bond length is 1.74 Å. The Fe(2)-N(3) bond length is 1.75 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded to one Ca(4), two equivalent Ca(1), two equivalent Ca(3), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-50°. In the second N site, N(2) is bonded to one Ca(1), one Ca(4), three equivalent Ca(2), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 14-50°. In the third N site, N(3) is bonded to one Ca(2), one Ca(3), three equivalent Ca(4), and one Fe(2) atom to form a mixture of distorted corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 16-63°. In the fourth N site, N(4) is bonded to one Ca(2), two equivalent Ca(1), two equivalent Ca(3), and one Fe(1) atom to form a mixture of corner and edge-sharing NCa5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-63°.