Na4BaO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted NaO4 tetrahedra that share corners with four equivalent Ba(1)O4 tetrahedra and edges with two equivalent Na(1)O4 tetrahedra. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. In the third Na site, Na(3) is bonded in a bent 150 degrees geometry to two equivalent O(2) atoms. In the fourth Na site, Na(4) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. Ba(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form BaO4 tetrahedra that share corners with two equivalent Ba(1)O4 tetrahedra and corners with four equivalent Na(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(1), two equivalent Na(2), and one Ba(1) atom. In the second O site, O(2) is bonded to one Na(4), two equivalent Na(3), and two equivalent Ba(1) atoms to form distorted corner-sharing OBa2Na3 trigonal bipyramids. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(1), two equivalent Na(2), and one Ba(1) atom.
Na4BaO3 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted NaO4 tetrahedra that share corners with four equivalent Ba(1)O4 tetrahedra and edges with two equivalent Na(1)O4 tetrahedra. There is one shorter (2.30 Å) and one longer (2.66 Å) Na(1)-O(1) bond length. There is one shorter (2.31 Å) and one longer (2.60 Å) Na(1)-O(3) bond length. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. There is one shorter (2.30 Å) and one longer (2.76 Å) Na(2)-O(1) bond length. There is one shorter (2.30 Å) and one longer (2.62 Å) Na(2)-O(3) bond length. In the third Na site, Na(3) is bonded in a bent 150 degrees geometry to two equivalent O(2) atoms. There is one shorter (2.12 Å) and one longer (2.13 Å) Na(3)-O(2) bond length. In the fourth Na site, Na(4) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Na(4)-O(1) bond length is 2.37 Å. The Na(4)-O(2) bond length is 2.31 Å. The Na(4)-O(3) bond length is 2.38 Å. Ba(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form BaO4 tetrahedra that share corners with two equivalent Ba(1)O4 tetrahedra and corners with four equivalent Na(1)O4 tetrahedra. The Ba(1)-O(1) bond length is 2.51 Å. The Ba(1)-O(3) bond length is 2.53 Å. There is one shorter (2.72 Å) and one longer (2.78 Å) Ba(1)-O(2) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(1), two equivalent Na(2), and one Ba(1) atom. In the second O site, O(2) is bonded to one Na(4), two equivalent Na(3), and two equivalent Ba(1) atoms to form distorted corner-sharing OBa2Na3 trigonal bipyramids. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(4), two equivalent Na(1), two equivalent Na(2), and one Ba(1) atom.