Materials Data on Na2Si2Se5 by Materials Project
Na2Si2Se5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 3.11–3.54 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 3.03–3.58 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four Se2- atoms to form corner-sharing SiSe4 tetrahedra. There are a spread of Si–Se bond distances ranging from 2.23–2.32 Å. In the second Si4+ site, Si4+ is bonded to four Se2- atoms to form corner-sharing SiSe4 tetrahedra. There are a spread of Si–Se bond distances ranging from 2.23–2.32 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Na1+ and one Si4+ atom to form distorted corner-sharing SeNa3Si tetrahedra. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the third Se2- site, Se2- is bonded in a water-like geometry to two equivalent Si4+ atoms. In the fourth Se2- site, Se2- is bonded in a 2-coordinate geometry to two Na1+ and two Si4+ atoms. In the fifth Se2- site, Se2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two equivalent Si4+ atoms.