Materials Data on Na2H2WO4 by Materials Project
(Na2WHO4)2H2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional and consists of eight hydrogen molecules and one Na2WHO4 framework. In the Na2WHO4 framework, there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to one H1+ and three O2- atoms. The Na–H bond length is 2.59 Å. There are a spread of Na–O bond distances ranging from 2.26–2.31 Å. In the second Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to one H1+ and four O2- atoms. The Na–H bond length is 2.69 Å. There are a spread of Na–O bond distances ranging from 2.29–2.40 Å. W4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 1.81–1.85 Å. H1+ is bonded in a water-like geometry to two Na1+ atoms. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and one W4+ atom to form distorted edge-sharing ONa3W trigonal pyramids. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Na1+ and one W4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and one W4+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Na1+ and one W4+ atom.