Na4FeAl3O8 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. In the third Na site, Na(3) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. In the fourth Na site, Na(4) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. Fe(1) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form FeO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. In the third Al site, Al(3) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(4), one Fe(1), and one Al(1) atom to form distorted ONa2AlFe trigonal pyramids that share corners with two equivalent O(4)Na2Al2 trigonal pyramids and corners with two equivalent O(2)Na2AlFe trigonal pyramids. In the second O site, O(2) is bonded to one Na(2), one Na(3), one Fe(1), and one Al(1) atom to form distorted ONa2AlFe trigonal pyramids that share corners with two equivalent O(3)Na2Al2 trigonal pyramids and corners with two equivalent O(1)Na2AlFe trigonal pyramids. In the third O site, O(3) is bonded to one Na(2), one Na(3), one Al(2), and one Al(3) atom to form distorted ONa2Al2 trigonal pyramids that share corners with two equivalent O(4)Na2Al2 trigonal pyramids and corners with two equivalent O(2)Na2AlFe trigonal pyramids. In the fourth O site, O(4) is bonded to one Na(1), one Na(4), one Al(2), and one Al(3) atom to form distorted ONa2Al2 trigonal pyramids that share corners with two equivalent O(3)Na2Al2 trigonal pyramids and corners with two equivalent O(1)Na2AlFe trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Al(3) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(1), and one Al(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Al(1), and one Al(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Fe(1), and one Al(3) atom.
Na4FeAl3O8 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form distorted NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Na(1)-O(1) bond length is 2.36 Å. The Na(1)-O(4) bond length is 2.37 Å. The Na(1)-O(5) bond length is 2.38 Å. The Na(1)-O(6) bond length is 2.42 Å. In the second Na site, Na(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Na(2)-O(2) bond length is 2.32 Å. The Na(2)-O(3) bond length is 2.35 Å. The Na(2)-O(5) bond length is 2.37 Å. The Na(2)-O(6) bond length is 2.40 Å. In the third Na site, Na(3) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form NaO4 tetrahedra that share corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Na(3)-O(2) bond length is 2.28 Å. The Na(3)-O(3) bond length is 2.33 Å. The Na(3)-O(7) bond length is 2.39 Å. The Na(3)-O(8) bond length is 2.32 Å. In the fourth Na site, Na(4) is bonded to one O(1), one O(4), one O(7), and one O(8) atom to form NaO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, corners with two equivalent Al(2)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Na(4)-O(1) bond length is 2.34 Å. The Na(4)-O(4) bond length is 2.38 Å. The Na(4)-O(7) bond length is 2.40 Å. The Na(4)-O(8) bond length is 2.38 Å. Fe(1) is bonded to one O(1), one O(2), one O(5), and one O(8) atom to form FeO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Fe(1)-O(1) bond length is 1.90 Å. The Fe(1)-O(2) bond length is 1.89 Å. The Fe(1)-O(5) bond length is 1.91 Å. The Fe(1)-O(8) bond length is 1.90 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. The Al(1)-O(1) bond length is 1.78 Å. The Al(1)-O(2) bond length is 1.78 Å. The Al(1)-O(6) bond length is 1.79 Å. The Al(1)-O(7) bond length is 1.79 Å. In the second Al site, Al(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Al(1)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The Al(2)-O(3) bond length is 1.78 Å. The Al(2)-O(4) bond length is 1.78 Å. The Al(2)-O(6) bond length is 1.79 Å. The Al(2)-O(7) bond length is 1.79 Å. In the third Al site, Al(3) is bonded to one O(3), one O(4), one O(5), and one O(8) atom to form AlO4 tetrahedra that share corners with two equivalent Na(1)O4 tetrahedra, corners with two equivalent Na(2)O4 tetrahedra, corners with two equivalent Na(3)O4 tetrahedra, corners with two equivalent Na(4)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. The Al(3)-O(3) bond length is 1.78 Å. The Al(3)-O(4) bond length is 1.78 Å. The Al(3)-O(5) bond length is 1.79 Å. The Al(3)-O(8) bond length is 1.78 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), one Na(4), one Fe(1), and one Al(1) atom to form distorted ONa2AlFe trigonal pyramids that share corners with two equivalent O(4)Na2Al2 trigonal pyramids and corners with two equivalent O(2)Na2AlFe trigonal pyramids. In the second O site, O(2) is bonded to one Na(2), one Na(3), one Fe(1), and one Al(1) atom to form distorted ONa2AlFe trigonal pyramids that share corners with two equivalent O(3)Na2Al2 trigonal pyramids and corners with two equivalent O(1)Na2AlFe trigonal pyramids. In the third O site, O(3) is bonded to one Na(2), one Na(3), one Al(2), and one Al(3) atom to form distorted ONa2Al2 trigonal pyramids that share corners with two equivalent O(4)Na2Al2 trigonal pyramids and corners with two equivalent O(2)Na2AlFe trigonal pyramids. In the fourth O site, O(4) is bonded to one Na(1), one Na(4), one Al(2), and one Al(3) atom to form distorted ONa2Al2 trigonal pyramids that share corners with two equivalent O(3)Na2Al2 trigonal pyramids and corners with two equivalent O(1)Na2AlFe trigonal pyramids. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Al(3) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(1), and one Al(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Al(1), and one Al(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(3), one Na(4), one Fe(1), and one Al(3) atom.