CsFeS2 crystallizes in the orthorhombic Immm space group. Cs(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form edge-sharing FeS4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 2-coordinate geometry to four equivalent Cs(1) and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded to four equivalent Cs(1) and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing SCs4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 10-79°.
CsFeS2 crystallizes in the orthorhombic Immm space group. Cs(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. All Cs(1)-S(1) bond lengths are 3.85 Å. There are two shorter (3.49 Å) and two longer (3.56 Å) Cs(1)-S(2) bond lengths. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form edge-sharing FeS4 tetrahedra. Both Fe(1)-S(1) bond lengths are 2.20 Å. Both Fe(1)-S(2) bond lengths are 2.21 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 2-coordinate geometry to four equivalent Cs(1) and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded to four equivalent Cs(1) and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing SCs4Fe2 octahedra. The corner-sharing octahedral tilt angles range from 10-79°.