Fe7S8 crystallizes in the trigonal P3_121 space group. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one S(4), two equivalent S(1), and two equivalent S(3) atoms. In the second Fe site, Fe(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the third Fe site, Fe(3) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 44-60°. In the fourth Fe site, Fe(4) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 50-60°. In the fifth Fe site, Fe(5) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 44-60°. There are four inequivalent S sites. In the first S site, S(4) is bonded in a 5-coordinate geometry to one Fe(1), one Fe(2), one Fe(3), one Fe(4), and one Fe(5) atom. In the second S site, S(1) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(3), one Fe(5), and two equivalent Fe(1) atoms. In the third S site, S(2) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(4), one Fe(5), and two equivalent Fe(3) atoms. In the fourth S site, S(3) is bonded in a 5-coordinate geometry to one Fe(4), two equivalent Fe(1), and two equivalent Fe(3) atoms.
Fe7S8 crystallizes in the trigonal P3_121 space group. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one S(4), two equivalent S(1), and two equivalent S(3) atoms. The Fe(1)-S(4) bond length is 2.10 Å. Both Fe(1)-S(1) bond lengths are 2.22 Å. Both Fe(1)-S(3) bond lengths are 2.31 Å. In the second Fe site, Fe(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. Both Fe(2)-S(1) bond lengths are 2.18 Å. Both Fe(2)-S(2) bond lengths are 2.36 Å. Both Fe(2)-S(4) bond lengths are 2.37 Å. In the third Fe site, Fe(3) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 44-60°. The Fe(3)-S(1) bond length is 2.19 Å. The Fe(3)-S(4) bond length is 2.40 Å. There is one shorter (2.24 Å) and one longer (2.30 Å) Fe(3)-S(2) bond length. There is one shorter (2.29 Å) and one longer (2.34 Å) Fe(3)-S(3) bond length. In the fourth Fe site, Fe(4) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 50-60°. Both Fe(4)-S(2) bond lengths are 2.41 Å. Both Fe(4)-S(3) bond lengths are 2.37 Å. Both Fe(4)-S(4) bond lengths are 2.20 Å. In the fifth Fe site, Fe(5) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form a mixture of distorted edge, face, and corner-sharing FeS6 octahedra. The corner-sharing octahedral tilt angles range from 44-60°. Both Fe(5)-S(1) bond lengths are 2.38 Å. Both Fe(5)-S(2) bond lengths are 2.49 Å. Both Fe(5)-S(4) bond lengths are 2.24 Å. There are four inequivalent S sites. In the first S site, S(4) is bonded in a 5-coordinate geometry to one Fe(1), one Fe(2), one Fe(3), one Fe(4), and one Fe(5) atom. In the second S site, S(1) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(3), one Fe(5), and two equivalent Fe(1) atoms. In the third S site, S(2) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(4), one Fe(5), and two equivalent Fe(3) atoms. In the fourth S site, S(3) is bonded in a 5-coordinate geometry to one Fe(4), two equivalent Fe(1), and two equivalent Fe(3) atoms.