DOE OSTI2020
CuFe2S3 is Enargite-like structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are four inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with five FeS4 tetrahedra, corners with five CuS4 tetrahedra, and an edgeedge with one FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.22–2.29 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with five FeS4 tetrahedra, corners with five CuS4 tetrahedra, and an edgeedge with one FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.21–2.24 Å. In the third Fe+2.50+ site, Fe+2.50+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with five FeS4 tetrahedra, corners with five CuS4 tetrahedra, and an edgeedge with one FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.21–2.29 Å. In the fourth Fe+2.50+ site, Fe+2.50+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with five FeS4 tetrahedra, corners with five CuS4 tetrahedra, and an edgeedge with one FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.23–2.29 Å. There are four inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CuS4 tetrahedra and corners with ten FeS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.28–2.31 Å. In the second Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CuS4 tetrahedra and corners with ten FeS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.28–2.34 Å. In the third Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CuS4 tetrahedra and corners with ten FeS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.27–2.33 Å. In the fourth Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CuS4 tetrahedra and corners with ten FeS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.27–2.32 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to three Fe+2.50+ and one Cu1+ atom to form a mixture of edge and corner-sharing SFe3Cu tetrahedra. In the second S2- site, S2- is bonded to three Fe+2.50+ and one Cu1+ atom to form a mixture of edge and corner-sharing SFe3Cu tetrahedra. In the third S2- site, S2- is bonded to two equivalent Fe+2.50+ and two Cu1+ atoms to form corner-sharing SFe2Cu2 tetrahedra. In the fourth S2- site, S2- is bonded to three Fe+2.50+ and one Cu1+ atom to form a mixture of edge and corner-sharing SFe3Cu tetrahedra. In the fifth S2- site, S2- is bonded to two equivalent Fe+2.50+ and two Cu1+ atoms to form corner-sharing SFe2Cu2 tetrahedra. In the sixth S2- site, S2- is bonded to three Fe+2.50+ and one Cu1+ atom to form a mixture of edge and corner-sharing SFe3Cu tetrahedra. In the seventh S2- site, S2- is bonded to two equivalent Fe+2.50+ and two Cu1+ atoms to form corner-sharing SFe2Cu2 tetrahedra. In the eighth S2- site, S2- is bonded to two equivalent Fe+2.50+ and two Cu1+ atoms to form corner-sharing SFe2Cu2 tetrahedra.