Materials Data on Na5TaO5 by Materials Project

Abstract

Na5TaO5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 trigonal pyramids that share corners with six NaO5 square pyramids, corners with two equivalent TaO5 trigonal bipyramids, a cornercorner with one NaO4 trigonal pyramid, edges with three NaO5 square pyramids, an edgeedge with one TaO5 trigonal bipyramid, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Na–O bond distances ranging from 2.30–2.45 Å. In the second Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share corners with two NaO5 square pyramids, corners with three equivalent TaO5 trigonal bipyramids, corners with four equivalent NaO4 trigonal pyramids, edges with four NaO5 square pyramids, an edgeedge with one TaO5 trigonal bipyramid, and edges with two equivalent NaO4 trigonal pyramids. There are a spread of Na–O bond distances ranging from 2.35–2.47 Å. In the third Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share corners with two equivalent NaO5 square pyramids, a cornercorner with one TaO5 trigonal bipyramid, corners with four equivalent NaO4 trigonal pyramids, edges with four equivalent NaO5 square pyramids, edges with two equivalent TaO5 trigonal bipyramids, and edges with two equivalent NaO4 trigonal pyramids. There are a spread of Na–O bond distances ranging from 2.31–2.48 Å. Ta5+ is bonded to five O2- atoms to form TaO5 trigonal bipyramids that share corners with seven NaO5 square pyramids, corners with four equivalent NaO4 trigonal pyramids, edges with four NaO5 square pyramids, and edges with two equivalent NaO4 trigonal pyramids. There are a spread of Ta–O bond distances ranging from 1.91–2.03 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Ta5+ atom to form distorted ONa5Ta octahedra that share corners with four equivalent ONa5Ta octahedra, corners with two equivalent ONa4Ta square pyramids, edges with four equivalent ONa5Ta octahedra, and edges with four equivalent ONa4Ta square pyramids. The corner-sharing octahedra tilt angles range from 16–31°. In the second O2- site, O2- is bonded to four Na1+ and one Ta5+ atom to form distorted ONa4Ta square pyramids that share corners with three ONa5Ta octahedra, corners with two equivalent ONa4Ta square pyramids, edges with six ONa5Ta octahedra, and an edgeedge with one ONa4Ta square pyramid. The corner-sharing octahedra tilt angles range from 31–68°. In the third O2- site, O2- is bonded to five Na1+ and one Ta5+ atom to form distorted ONa5Ta octahedra that share corners with four ONa5Ta octahedra, corners with two equivalent ONa4Ta square pyramids, edges with four ONa5Ta octahedra, and edges with four equivalent ONa4Ta square pyramids. The corner-sharing octahedra tilt angles range from 8–32°.