DOE OSTI2020
Mg1Mo6S8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form distorted MgS4 trigonal pyramids that share corners with twelve MoS5 square pyramids and an edgeedge with one MoS5 square pyramid. There are a spread of Mg–S bond distances ranging from 2.46–2.57 Å. In the second Mg2+ site, Mg2+ is bonded to four S2- atoms to form distorted MgS4 trigonal pyramids that share corners with twelve MoS5 square pyramids and an edgeedge with one MoS5 square pyramid. There are a spread of Mg–S bond distances ranging from 2.46–2.58 Å. There are twelve inequivalent Mo+2.33+ sites. In the first Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.51 Å. In the second Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two equivalent MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.52 Å. In the third Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with three equivalent MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.52 Å. In the fourth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with three MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.55 Å. In the fifth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, a cornercorner with one MgS4 trigonal pyramid, edges with five MoS5 square pyramids, and an edgeedge with one MgS4 trigonal pyramid. There are a spread of Mo–S bond distances ranging from 2.42–2.54 Å. In the sixth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.44–2.48 Å. In the seventh Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, a cornercorner with one MgS4 trigonal pyramid, edges with five MoS5 square pyramids, and an edgeedge with one MgS4 trigonal pyramid. There are a spread of Mo–S bond distances ranging from 2.43–2.55 Å. In the eighth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two equivalent MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.44–2.52 Å. In the ninth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, a cornercorner with one MgS4 trigonal pyramid, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.48 Å. In the tenth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two equivalent MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.42–2.52 Å. In the eleventh Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with three MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.44–2.52 Å. In the twelfth Mo+2.33+ site, Mo+2.33+ is bonded to five S2- atoms to form MoS5 square pyramids that share corners with four MoS5 square pyramids, corners with two MgS4 trigonal pyramids, and edges with five MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.43–2.52 Å. There are sixteen inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo+2.33+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo+2.33+ atoms. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to one Mg2+ and three Mo+2.33+ atoms. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the sixth S2- site, S2- is bonded in a 1-coordinate geometry to one Mg2+ and three Mo+2.33+ atoms. In the seventh S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the eighth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the ninth S2- site, S2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo+2.33+ atoms. In the tenth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the eleventh S2- site, S2- is bonded in a 1-coordinate geometry to one Mg2+ and three Mo+2.33+ atoms. In the twelfth S2- site, S2- is bonded in a 5-coordinate geometry to one Mg2+ and four Mo+2.33+ atoms. In the thirteenth S2- site, S2- is bonded in a 1-coordinate geometry to one Mg2+ and three Mo+2.33+ atoms. In the fourteenth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the fifteenth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the sixteenth S2- site, S2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms.