Materials Data on Na2Si2O5 by Materials Project

Abstract

Na2Si2O5 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share corners with four equivalent NaO5 square pyramids, corners with four SiO4 tetrahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.40–2.59 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.96 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NaO5 square pyramids, corners with three SiO4 tetrahedra, and an edgeedge with one NaO5 square pyramid. There is one shorter (1.60 Å) and three longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NaO5 square pyramids and corners with three SiO4 tetrahedra. There is one shorter (1.60 Å) and three longer (1.66 Å) Si–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Si4+ atoms.