DOE OSTI2020
Fe5Ni7S16 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with four FeS6 octahedra and corners with eight NiS6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Fe–S bond distances ranging from 2.10–2.14 Å. In the second Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with two equivalent FeS4 tetrahedra, corners with four NiS4 tetrahedra, an edgeedge with one FeS6 octahedra, and edges with five NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.26–2.28 Å. In the third Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.26–2.31 Å. In the fourth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with two equivalent NiS6 octahedra, and edges with four FeS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.27–2.30 Å. In the fifth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.27–2.29 Å. In the sixth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with two equivalent NiS6 octahedra, and edges with four FeS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.28–2.30 Å. In the seventh Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with two FeS6 octahedra, and edges with four NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.26–2.28 Å. In the eighth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with six NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.27–2.30 Å. In the ninth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share a cornercorner with one FeS4 tetrahedra, corners with five NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.26–2.31 Å. In the tenth Fe3+ site, Fe3+ is bonded to six S2- atoms to form FeS6 octahedra that share a cornercorner with one FeS4 tetrahedra, corners with five NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Fe–S bond distances ranging from 2.26–2.31 Å. There are fourteen inequivalent Ni+2.43+ sites. In the first Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with three equivalent FeS4 tetrahedra, corners with three equivalent NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Ni–S bond distances ranging from 2.30–2.33 Å. In the second Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with four NiS6 octahedra and corners with eight FeS6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. All Ni–S bond lengths are 2.17 Å. In the third Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with two equivalent FeS4 tetrahedra, corners with four NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Ni–S bond distances ranging from 2.29–2.34 Å. In the fourth Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with five NiS6 octahedra and corners with seven FeS6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Ni–S bond distances ranging from 2.17–2.19 Å. In the fifth Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with two equivalent FeS4 tetrahedra, corners with four NiS4 tetrahedra, edges with three FeS6 octahedra, and edges with three NiS6 octahedra. There are a spread of Ni–S bond distances ranging from 2.29–2.34 Å. In the sixth Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with five NiS6 octahedra and corners with seven FeS6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Ni–S bond distances ranging from 2.17–2.20 Å. In the seventh Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with four NiS6 octahedra and corners with eight FeS6 octahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are one shorter (2.16 Å) and three longer (2.17 Å) Ni–S bond lengths. In the eighth Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with six NiS4 tetrahedra and edges with six FeS6 octahedra. There are two shorter (2.30 Å) and four longer (2.31 Å) Ni–S bond lengths. In the ninth Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with four NiS6 octahedra and corners with eight FeS6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Ni–S bond distances ranging from 2.16–2.18 Å. In the tenth Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with six NiS4 tetrahedra, edges with two equivalent NiS6 octahedra, and edges with four FeS6 octahedra. There are a spread of Ni–S bond distances ranging from 2.29–2.31 Å. In the eleventh Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with six NiS4 tetrahedra, edges with two equivalent NiS6 octahedra, and edges with four FeS6 octahedra. There are four shorter (2.30 Å) and two longer (2.31 Å) Ni–S bond lengths. In the twelfth Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with five NiS6 octahedra and corners with seven FeS6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are one shorter (2.17 Å) and three longer (2.18 Å) Ni–S bond lengths. In the thirteenth Ni+2.43+ site, Ni+2.43+ is bonded to six S2- atoms to form NiS6 octahedra that share a cornercorner with one FeS4 tetrahedra, corners with five NiS4 tetrahedra, an edgeedge with one NiS6 octahedra, and edges with five FeS6 octahedra. There are a spread of Ni–S bond distances ranging from 2.30–2.34 Å. In the fourteenth Ni+2.43+ site, Ni+2.43+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with five FeS6 octahedra and corners with seven NiS6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Ni–S bond distances ranging from 2.17–2.20 Å. There are thirty-two inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Fe3+ and three Ni+2.43+ atoms. In the second S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted corner-sharing SFeNi3 trigonal pyramids. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the fourth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the fifth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the sixth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the seventh S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the eighth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the ninth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with six SFe2Ni2 trigonal pyramids and an edgeedge with one SFeNi3 trigonal pyramid. In the tenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the eleventh S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Ni+2.43+ atom. In the twelfth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with three SFe2Ni2 trigonal pyramids and an edgeedge with one SFeNi3 trigonal pyramid. In the thirteenth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with four SFe2Ni2 trigonal pyramids and edges with two SFeNi3 trigonal pyramids. In the fourteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Ni+2.43+ atom. In the fifteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the sixteenth S2- site, S2- is bonded to two Fe3+ and two Ni+2.43+ atoms to form distorted corner-sharing SFe2Ni2 trigonal pyramids. In the seventeenth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form a mixture of distorted edge and corner-sharing SFeNi3 trigonal pyramids. In the eighteenth S2- site, S2- is bonded to two Fe3+ and two Ni+2.43+ atoms to form a mixture of distorted edge and corner-sharing SFe2Ni2 trigonal pyramids. In the nineteenth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the twentieth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the twenty-first S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the twenty-second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the twenty-third S2- site, S2- is bonded to two Fe3+ and two Ni+2.43+ atoms to form a mixture of distorted edge and corner-sharing SFe2Ni2 trigonal pyramids. In the twenty-fourth S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the twenty-fifth S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Fe3+ and three Ni+2.43+ atoms. In the twenty-sixth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Ni+2.43+ atom. In the twenty-seventh S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Ni+2.43+ atom. In the twenty-eighth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with six SFeNi3 trigonal pyramids and an edgeedge with one SFe2Ni2 trigonal pyramid. In the twenty-ninth S2- site, S2- is bonded to two Fe3+ and two Ni+2.43+ atoms to form a mixture of distorted edge and corner-sharing SFe2Ni2 trigonal pyramids. In the thirtieth S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with three SFeNi3 trigonal pyramids and edges with two SFe2Ni2 trigonal pyramids. In the thirty-first S2- site, S2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Ni+2.43+ atoms. In the thirty-second S2- site, S2- is bonded to one Fe3+ and three Ni+2.43+ atoms to form distorted SFeNi3 trigonal pyramids that share corners with three SFeNi3 trigonal pyramids and edges with two SFe2Ni2 trigonal pyramids.