Materials Data on KNa3W2O17 by Materials Project
KNa3W2O17 crystallizes in the hexagonal P6_3/m space group. The structure is two-dimensional and consists of two KNa3W2O17 sheets oriented in the (0, 0, 1) direction. K is bonded in a 6-coordinate geometry to six equivalent O atoms. All K–O bond lengths are 2.75 Å. Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with two equivalent WO4 tetrahedra and faces with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.37–2.63 Å. W is bonded to four O atoms to form WO4 tetrahedra that share corners with three equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There is one shorter (1.81 Å) and three longer (1.82 Å) W–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to three equivalent Na and one W atom. In the second O site, O is bonded in an L-shaped geometry to one K and one Na atom. In the third O site, O is bonded in a distorted L-shaped geometry to two equivalent Na atoms. In the fourth O site, O is bonded in a single-bond geometry to one W atom.