Materials Data on Na5CuO4 by Materials Project
Na5CuO4 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with two equivalent CuO4 tetrahedra, corners with ten NaO4 tetrahedra, an edgeedge with one CuO4 tetrahedra, and edges with three NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.31–2.41 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four equivalent CuO4 tetrahedra, corners with eight equivalent NaO4 tetrahedra, and edges with four equivalent NaO4 tetrahedra. There are two shorter (2.30 Å) and two longer (2.33 Å) Na–O bond lengths. Cu3+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with twelve NaO4 tetrahedra and edges with four equivalent NaO4 tetrahedra. There is two shorter (1.94 Å) and two longer (1.96 Å) Cu–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Cu3+ atom to form a mixture of edge and corner-sharing ONa5Cu octahedra. The corner-sharing octahedra tilt angles range from 57–60°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Cu3+ atom.