Ba6Fe8S15 crystallizes in the tetragonal I4/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one S(1), one S(2), one S(3), and six equivalent S(4) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one S(1), four equivalent S(3), and four equivalent S(4) atoms. Fe(1) is bonded to one S(2), one S(3), and two equivalent S(4) atoms to form a mixture of corner and edge-sharing FeS4 tetrahedra. There are four inequivalent S sites. In the first S site, S(4) is bonded in a 6-coordinate geometry to one Ba(2), three equivalent Ba(1), and two equivalent Fe(1) atoms. In the second S site, S(1) is bonded to two equivalent Ba(2) and four equivalent Ba(1) atoms to form corner-sharing SBa6 octahedra. The corner-sharing octahedral tilt angles are 56°. In the third S site, S(2) is bonded to two equivalent Ba(1) and four equivalent Fe(1) atoms to form distorted corner-sharing SBa2Fe4 octahedra. The corner-sharing octahedral tilt angles are 56°. In the fourth S site, S(3) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Ba(2), and two equivalent Fe(1) atoms.
Ba6Fe8S15 crystallizes in the tetragonal I4/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one S(1), one S(2), one S(3), and six equivalent S(4) atoms. The Ba(1)-S(1) bond length is 3.25 Å. The Ba(1)-S(2) bond length is 3.22 Å. The Ba(1)-S(3) bond length is 3.13 Å. There are a spread of Ba(1)-S(4) bond distances ranging from 3.36-3.52 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one S(1), four equivalent S(3), and four equivalent S(4) atoms. The Ba(2)-S(1) bond length is 3.07 Å. All Ba(2)-S(3) bond lengths are 3.28 Å. All Ba(2)-S(4) bond lengths are 3.37 Å. Fe(1) is bonded to one S(2), one S(3), and two equivalent S(4) atoms to form a mixture of corner and edge-sharing FeS4 tetrahedra. The Fe(1)-S(2) bond length is 2.25 Å. The Fe(1)-S(3) bond length is 2.21 Å. There is one shorter (2.26 Å) and one longer (2.27 Å) Fe(1)-S(4) bond length. There are four inequivalent S sites. In the first S site, S(4) is bonded in a 6-coordinate geometry to one Ba(2), three equivalent Ba(1), and two equivalent Fe(1) atoms. In the second S site, S(1) is bonded to two equivalent Ba(2) and four equivalent Ba(1) atoms to form corner-sharing SBa6 octahedra. The corner-sharing octahedral tilt angles are 56°. In the third S site, S(2) is bonded to two equivalent Ba(1) and four equivalent Fe(1) atoms to form distorted corner-sharing SBa2Fe4 octahedra. The corner-sharing octahedral tilt angles are 56°. In the fourth S site, S(3) is bonded in a 5-coordinate geometry to one Ba(1), two equivalent Ba(2), and two equivalent Fe(1) atoms.