Materials Data on Na2Te2O5 by Materials Project
Na2Te2O5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 pentagonal bipyramids that share a cornercorner with one NaO6 octahedra, corners with six equivalent NaO7 pentagonal bipyramids, and edges with two equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are a spread of Na–O bond distances ranging from 2.39–2.85 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with four equivalent NaO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, edges with two equivalent NaO6 octahedra, and edges with two equivalent NaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 22–26°. There are a spread of Na–O bond distances ranging from 2.28–2.61 Å. There are two inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.88–2.43 Å. In the second Te4+ site, Te4+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.86–2.23 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Te4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two Te4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Te4+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Te4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Te4+ atom.