FeS crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one S(3), two equivalent S(2), and three equivalent S(1) atoms. In the second Fe site, Fe(2) is bonded to one S(1), two equivalent S(2), and two equivalent S(3) atoms to form distorted corner-sharing FeS5 trigonal bipyramids. In the third Fe site, Fe(3) is bonded in a 6-coordinate geometry to one S(1), two equivalent S(2), and three equivalent S(3) atoms. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(3), and three equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Fe(1), two equivalent Fe(2), and three equivalent Fe(3) atoms.
FeS crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one S(3), two equivalent S(2), and three equivalent S(1) atoms. The Fe(1)-S(3) bond length is 2.58 Å. There is one shorter (2.24 Å) and one longer (2.30 Å) Fe(1)-S(2) bond length. There are a spread of Fe(1)-S(1) bond distances ranging from 2.23-2.27 Å. In the second Fe site, Fe(2) is bonded to one S(1), two equivalent S(2), and two equivalent S(3) atoms to form distorted corner-sharing FeS5 trigonal bipyramids. The Fe(2)-S(1) bond length is 2.24 Å. Both Fe(2)-S(2) bond lengths are 2.25 Å. There is one shorter (2.14 Å) and one longer (2.19 Å) Fe(2)-S(3) bond length. In the third Fe site, Fe(3) is bonded in a 6-coordinate geometry to one S(1), two equivalent S(2), and three equivalent S(3) atoms. The Fe(3)-S(1) bond length is 2.30 Å. There is one shorter (2.49 Å) and one longer (2.50 Å) Fe(3)-S(2) bond length. There are a spread of Fe(3)-S(3) bond distances ranging from 2.16-2.38 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to one Fe(2), one Fe(3), and three equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), and two equivalent Fe(3) atoms. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Fe(1), two equivalent Fe(2), and three equivalent Fe(3) atoms.