Materials Data on BaNa2O2 by Materials Project

Abstract

Na2BaO2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. All Na–O bond lengths are 2.34 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four equivalent NaO4 tetrahedra, corners with four equivalent BaO5 trigonal bipyramids, and edges with three equivalent BaO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.29–2.45 Å. Ba2+ is bonded to five O2- atoms to form distorted BaO5 trigonal bipyramids that share corners with four equivalent NaO4 tetrahedra, corners with four equivalent BaO5 trigonal bipyramids, edges with three equivalent NaO4 tetrahedra, and edges with two equivalent BaO5 trigonal bipyramids. There are a spread of Ba–O bond distances ranging from 2.72–2.75 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and three equivalent Ba2+ atoms to form a mixture of distorted edge and corner-sharing OBa3Na3 octahedra. The corner-sharing octahedra tilt angles range from 26–63°. In the second O2- site, O2- is bonded to four Na1+ and two equivalent Ba2+ atoms to form a mixture of distorted edge and corner-sharing OBa2Na4 octahedra. The corner-sharing octahedra tilt angles range from 26–54°.