Materials Data on Na2H4WO6 by Materials Project
H4Na2WO6 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with four equivalent WO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, an edgeedge with one NaO6 octahedra, and edges with two equivalent NaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.44–2.54 Å. In the second Na1+ site, Na1+ is bonded to five O2- atoms to form NaO5 trigonal bipyramids that share a cornercorner with one NaO6 octahedra, corners with three equivalent WO4 tetrahedra, and edges with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 73°. There are a spread of Na–O bond distances ranging from 2.33–2.40 Å. W6+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with four equivalent NaO6 octahedra and corners with three equivalent NaO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 51–62°. There are a spread of W–O bond distances ranging from 1.80–1.83 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Na1+ and one W6+ atom. In the second O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and one W6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one W6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one W6+ atom. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+ and two H1+ atoms.