Materials Data on Na2Mo15Se19 by Materials Project
Na2Mo15Se19 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Na1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are three shorter (3.16 Å) and one longer (3.51 Å) Na–Se bond lengths. There are three inequivalent Mo+2.40+ sites. In the first Mo+2.40+ site, Mo+2.40+ is bonded in a see-saw-like geometry to four Se2- atoms. There are two shorter (2.57 Å) and two longer (2.61 Å) Mo–Se bond lengths. In the second Mo+2.40+ site, Mo+2.40+ 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 2.56–2.66 Å. In the third Mo+2.40+ site, Mo+2.40+ 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. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 10-coordinate geometry to one Na1+ and three equivalent Mo+2.40+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.40+ atoms. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to three equivalent Mo+2.40+ atoms. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to one Na1+ and four Mo+2.40+ atoms. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Mo+2.40+ atoms.