Materials Data on BaNa6O4 by Materials Project
Na6BaO4 crystallizes in the tetragonal P4_2/nmc space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four equivalent O2- atoms to form distorted NaO4 tetrahedra that share corners with two equivalent BaO4 tetrahedra, corners with twelve NaO4 tetrahedra, an edgeedge with one BaO4 tetrahedra, and edges with four NaO4 tetrahedra. There are two shorter (2.36 Å) and two longer (2.69 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to four equivalent O2- atoms to form NaO4 tetrahedra that share corners with four equivalent BaO4 tetrahedra, corners with eight equivalent NaO4 tetrahedra, and edges with six NaO4 tetrahedra. There are two shorter (2.34 Å) and two longer (2.39 Å) Na–O bond lengths. Ba2+ is bonded to four equivalent O2- atoms to form BaO4 tetrahedra that share corners with sixteen NaO4 tetrahedra and edges with four equivalent NaO4 tetrahedra. All Ba–O bond lengths are 2.56 Å. O2- is bonded to six Na1+ and one Ba2+ atom to form a mixture of distorted corner and edge-sharing OBaNa6 pentagonal bipyramids.