Materials Data on Na2Si2O5 by Materials Project

Na2Si2O5 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with four equivalent SiO4 tetrahedra, corners with four equivalent NaO5 trigonal bipyramids, an edgeedge with one SiO4 tetrahedra, and edges with four equivalent NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.32–2.64 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent SiO4 tetrahedra, corners with four equivalent NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four equivalent Na1+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Si4+ atoms.