DOE OSTI2020
Mo15Tl3Se19 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are nine inequivalent Mo+2.33+ sites. In the first Mo+2.33+ site, Mo+2.33+ is bonded in a see-saw-like geometry to four Se2- atoms. There are two shorter (2.58 Å) and two longer (2.61 Å) Mo–Se bond lengths. In the second Mo+2.33+ site, Mo+2.33+ is bonded in a see-saw-like geometry to four Se2- atoms. All Mo–Se bond lengths are 2.59 Å. In the third Mo+2.33+ site, Mo+2.33+ is bonded to one Tl1+ and four Se2- atoms to form a mixture of edge and corner-sharing MoTlSe4 trigonal bipyramids. The Mo–Tl bond length is 2.92 Å. There are a spread of Mo–Se bond distances ranging from 2.59–2.69 Å. In the fourth Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.52–2.74 Å. In the fifth Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with four MoSe5 square pyramids, edges with three MoSe5 square pyramids, and an edgeedge with one MoTlSe4 trigonal bipyramid. There are a spread of Mo–Se bond distances ranging from 2.57–2.74 Å. In the sixth Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with four MoSe5 square pyramids, edges with three MoSe5 square pyramids, and an edgeedge with one MoTlSe4 trigonal bipyramid. There are a spread of Mo–Se bond distances ranging from 2.55–2.75 Å. In the seventh Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.52–2.75 Å. In the eighth Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.55–2.74 Å. In the ninth Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form MoSe5 square pyramids that share corners with three MoSe5 square pyramids, a cornercorner with one MoTlSe4 trigonal bipyramid, and edges with five MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.58–2.75 Å. There are two inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Tl–Se bond distances ranging from 3.15–3.74 Å. In the second Tl1+ site, Tl1+ is bonded in a 7-coordinate geometry to one Mo+2.33+ and six Se2- atoms. There are a spread of Tl–Se bond distances ranging from 2.87–3.25 Å. There are eleven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.33+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Mo+2.33+ and one Tl1+ atom. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the sixth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the seventh Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the ninth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Tl1+ atom. In the tenth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Mo+2.33+ and two Tl1+ atoms. In the eleventh Se2- site, Se2- is bonded in a 4-coordinate geometry to three Mo+2.33+ and one Tl1+ atom.