Materials Data on NaCu2O3 by Materials Project
NaCu2O3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with four equivalent CuO6 octahedra, edges with three equivalent NaO6 octahedra, and edges with seven CuO6 octahedra. The corner-sharing octahedra tilt angles range from 13–20°. There are a spread of Na–O bond distances ranging from 2.30–2.40 Å. There are three inequivalent Cu+2.50+ sites. In the first Cu+2.50+ site, Cu+2.50+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four equivalent NaO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with five CuO6 octahedra. The corner-sharing octahedra tilt angles range from 13–20°. There are a spread of Cu–O bond distances ranging from 2.03–2.12 Å. In the second Cu+2.50+ site, Cu+2.50+ is bonded in a distorted square co-planar geometry to six O2- atoms. There are four shorter (1.90 Å) and two longer (2.62 Å) Cu–O bond lengths. In the third Cu+2.50+ site, Cu+2.50+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with four equivalent CuO6 octahedra, edges with four equivalent CuO6 octahedra, and edges with six equivalent NaO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are two shorter (1.89 Å) and four longer (2.24 Å) Cu–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Na1+ and four Cu+2.50+ atoms to form a mixture of distorted edge and corner-sharing ONa2Cu4 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Na1+ and four Cu+2.50+ atoms.