Materials Data on NaSi2W2O5 by Materials Project
NaNaSi4(W2O5)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four sodium molecules and one NaSi4(W2O5)2 framework. In the NaSi4(W2O5)2 framework, Na1+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–2.54 Å. There are four inequivalent W+4.50+ sites. In the first W+4.50+ site, W+4.50+ is bonded in a bent 150 degrees geometry to two O2- atoms. There are one shorter (2.05 Å) and one longer (2.19 Å) W–O bond lengths. In the second W+4.50+ site, W+4.50+ is bonded in a linear geometry to two O2- atoms. There are one shorter (2.17 Å) and one longer (2.30 Å) W–O bond lengths. In the third W+4.50+ site, W+4.50+ is bonded in a single-bond geometry to one O2- atom. The W–O bond length is 2.14 Å. In the fourth W+4.50+ site, W+4.50+ is bonded in a single-bond geometry to one O2- atom. The W–O bond length is 2.20 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the second Si site, Si is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the third Si site, Si is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the fourth Si site, Si is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one W+4.50+, and one Si atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one W+4.50+, and one Si atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Si atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two Si atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two W+4.50+, and one Si atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two W+4.50+ and one Si atom.