Materials Data on Na14Cu2O9 by Materials Project

Abstract

Na14Cu2O9 crystallizes in the trigonal P-3 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 NaO4 tetrahedra that share a cornercorner with one CuO4 tetrahedra, corners with fourteen NaO4 tetrahedra, an edgeedge with one CuO4 tetrahedra, and edges with four NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.31–2.44 Å. In the second Na1+ site, Na1+ is bonded to four equivalent O2- atoms to form NaO4 tetrahedra that share corners with two equivalent CuO4 tetrahedra, corners with twelve NaO4 tetrahedra, an edgeedge with one CuO4 tetrahedra, and edges with four NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.33–2.41 Å. In the third Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with three equivalent CuO4 tetrahedra, corners with ten NaO4 tetrahedra, and edges with six NaO4 tetrahedra. There are three shorter (2.35 Å) and one longer (2.36 Å) Na–O bond lengths. Cu2+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with twelve NaO4 tetrahedra and edges with six NaO4 tetrahedra. There are one shorter (2.00 Å) and three longer (2.10 Å) Cu–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to six Na1+ and one Cu2+ atom to form a mixture of distorted edge and corner-sharing ONa6Cu pentagonal bipyramids. In the second O2- site, O2- is bonded in a 7-coordinate geometry to six equivalent Na1+ and one Cu2+ atom. In the third O2- site, O2- is bonded in a body-centered cubic geometry to eight Na1+ atoms.