Na2Li2CoO4 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(13), one O(14), one O(15), one O(3), and one O(4) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(13), one O(14), one O(16), one O(2), one O(3), and one O(4) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(9) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(15), one O(3), one O(5), one O(7), and one O(8) atom. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(5), one O(6), and one O(8) atom. In the sixth Na site, Na(6) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(9) atom. In the seventh Na site, Na(7) is bonded to one O(1), one O(10), one O(12), one O(14), one O(2), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Co(3)O4 tetrahedra, corners with two equivalent Li(8)O4 trigonal pyramids,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra,  an edgeedge with one Li(6)O4 tetrahedra,  an edgeedge with one Li(7)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(15), one O(16), one O(7), and one O(8) atom. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(3), one O(4), and one O(8) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the second Li site, Li(2) is bonded to one O(10), one O(3), one O(5), and one O(9) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, corners with two equivalent Co(3)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. In the third Li site, Li(3) is bonded in a 4-coordinate geometry to one O(12), one O(14), one O(7), and one O(8) atom. In the fourth Li site, Li(4) is bonded to one O(13), one O(14), one O(7), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra, corners with two equivalent Li(5)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid,  a cornercorner with one Li(8)O4 trigonal pyramid,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Co(3)O4 tetrahedra. In the fifth Li site, Li(5) is bonded to one O(10), one O(13), one O(14), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid,  a cornercorner with one Li(8)O4 trigonal pyramid,  an edgeedge with one Na(7)O6 octahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Co(3)O4 tetrahedra. In the sixth Li site, Li(6) is bonded to one O(1), one O(11), one O(12), and one O(15) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, corners with two equivalent Li(7)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. In the seventh Li site, Li(7) is bonded to one O(11), one O(12), one O(16), and one O(2) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, corners with two equivalent Li(6)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. In the eighth Li site, Li(8) is bonded to one O(1), one O(11), one O(13), and one O(2) atom to form distorted LiO4 trigonal pyramids that share corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, corners with two equivalent Co(1)O4 tetrahedra,  an edgeedge with one Li(6)O4 tetrahedra,  an edgeedge with one Li(7)O4 tetrahedra, and  an edgeedge with one Co(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 75-76°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra, corners with two equivalent Li(8)O4 trigonal pyramids,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. In the second Co site, Co(2) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. In the third Co site, Co(3) is bonded to one O(10), one O(11), one O(13), and one O(9) atom to form CoO4 tetrahedra that share corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra, corners with two equivalent Li(2)O4 trigonal pyramids,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 77-82°. In the fourth Co site, Co(4) is bonded in a 4-coordinate geometry to one O(12), one O(14), one O(15), and one O(16) atom. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(7), one Li(6), one Li(8), and one Co(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(7), one Li(7), one Li(8), and one Co(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Li(1), one Li(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Li(1), and one Co(2) atom. In the fifth O site, O(5) is bonded in a distorted square pyramidal geometry to one Na(4), one Na(5), one Na(6), one Li(2), and one Co(1) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Na(3), one Na(5), one Na(6), and one Co(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(4), one Na(6), one Na(8), one Li(3), one Li(4), and one Co(2) atom. In the eighth O site, O(8) is bonded in a 7-coordinate geometry to one Na(4), one Na(5), one Na(8), one Li(1), one Li(3), one Li(5), and one Co(2) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Na(3), one Na(6), one Na(7), one Li(2), one Li(4), and one Co(3) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(5), one Na(7), one Li(1), one Li(2), one Li(5), and one Co(3) atom. In the eleventh O site, O(11) is bonded in a 7-coordinate geometry to one Na(5), one Na(6), one Na(8), one Li(6), one Li(7), one Li(8), and one Co(3) atom. In the twelfth O site, O(12) is bonded in a 7-coordinate geometry to one Na(5), one Na(6), one Na(7), one Li(3), one Li(6), one Li(7), and one Co(4) atom. In the thirteenth O site, O(13) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(8), one Li(4), one Li(5), one Li(8), and one Co(3) atom. In the fourteenth O site, O(14) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(7), one Li(3), one Li(4), one Li(5), and one Co(4) atom. In the fifteenth O site, O(15) is bonded in a 5-coordinate geometry to one Na(1), one Na(4), one Na(8), one Li(6), and one Co(4) atom. In the sixteenth O site, O(16) is bonded in a see-saw-like geometry to one Na(2), one Na(8), one Li(7), and one Co(4) atom.
Na2Li2CoO4 crystallizes in the triclinic P1 space group. There are eight inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(13), one O(14), one O(15), one O(3), and one O(4) atom. The Na(1)-O(1) bond length is 2.40 Å. The Na(1)-O(13) bond length is 2.68 Å. The Na(1)-O(14) bond length is 2.87 Å. The Na(1)-O(15) bond length is 2.29 Å. The Na(1)-O(3) bond length is 2.47 Å. The Na(1)-O(4) bond length is 2.35 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(13), one O(14), one O(16), one O(2), one O(3), and one O(4) atom. The Na(2)-O(13) bond length is 2.56 Å. The Na(2)-O(14) bond length is 2.66 Å. The Na(2)-O(16) bond length is 2.27 Å. The Na(2)-O(2) bond length is 2.40 Å. The Na(2)-O(3) bond length is 2.47 Å. The Na(2)-O(4) bond length is 2.35 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(9) atom. The Na(3)-O(1) bond length is 2.56 Å. The Na(3)-O(2) bond length is 2.79 Å. The Na(3)-O(4) bond length is 2.70 Å. The Na(3)-O(6) bond length is 2.32 Å. The Na(3)-O(9) bond length is 2.77 Å. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(15), one O(3), one O(5), one O(7), and one O(8) atom. The Na(4)-O(15) bond length is 2.74 Å. The Na(4)-O(3) bond length is 2.84 Å. The Na(4)-O(5) bond length is 2.42 Å. The Na(4)-O(7) bond length is 2.81 Å. The Na(4)-O(8) bond length is 2.88 Å. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(5), one O(6), and one O(8) atom. The Na(5)-O(10) bond length is 2.43 Å. The Na(5)-O(11) bond length is 2.67 Å. The Na(5)-O(12) bond length is 2.64 Å. The Na(5)-O(5) bond length is 2.38 Å. The Na(5)-O(6) bond length is 2.35 Å. The Na(5)-O(8) bond length is 2.46 Å. In the sixth Na site, Na(6) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(9) atom. The Na(6)-O(11) bond length is 2.69 Å. The Na(6)-O(12) bond length is 2.48 Å. The Na(6)-O(5) bond length is 2.45 Å. The Na(6)-O(6) bond length is 2.36 Å. The Na(6)-O(7) bond length is 2.33 Å. The Na(6)-O(9) bond length is 2.33 Å. In the seventh Na site, Na(7) is bonded to one O(1), one O(10), one O(12), one O(14), one O(2), and one O(9) atom to form distorted NaO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Co(3)O4 tetrahedra, corners with two equivalent Li(8)O4 trigonal pyramids,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra,  an edgeedge with one Li(6)O4 tetrahedra,  an edgeedge with one Li(7)O4 tetrahedra,  an edgeedge with one Co(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The Na(7)-O(1) bond length is 2.50 Å. The Na(7)-O(10) bond length is 2.78 Å. The Na(7)-O(12) bond length is 2.44 Å. The Na(7)-O(14) bond length is 2.36 Å. The Na(7)-O(2) bond length is 2.51 Å. The Na(7)-O(9) bond length is 2.59 Å. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(15), one O(16), one O(7), and one O(8) atom. The Na(8)-O(11) bond length is 2.52 Å. The Na(8)-O(13) bond length is 2.54 Å. The Na(8)-O(15) bond length is 2.33 Å. The Na(8)-O(16) bond length is 2.31 Å. The Na(8)-O(7) bond length is 2.60 Å. The Na(8)-O(8) bond length is 2.76 Å. There are eight inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(3), one O(4), and one O(8) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Na(7)O6 octahedra,  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra,  an edgeedge with one Co(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. The Li(1)-O(10) bond length is 2.02 Å. The Li(1)-O(3) bond length is 1.95 Å. The Li(1)-O(4) bond length is 1.92 Å. The Li(1)-O(8) bond length is 2.01 Å. In the second Li site, Li(2) is bonded to one O(10), one O(3), one O(5), and one O(9) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, corners with two equivalent Co(3)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Co(1)O4 tetrahedra. The Li(2)-O(10) bond length is 2.04 Å. The Li(2)-O(3) bond length is 1.98 Å. The Li(2)-O(5) bond length is 2.00 Å. The Li(2)-O(9) bond length is 1.92 Å. In the third Li site, Li(3) is bonded in a 4-coordinate geometry to one O(12), one O(14), one O(7), and one O(8) atom. The Li(3)-O(12) bond length is 2.20 Å. The Li(3)-O(14) bond length is 2.10 Å. The Li(3)-O(7) bond length is 1.90 Å. The Li(3)-O(8) bond length is 1.93 Å. In the fourth Li site, Li(4) is bonded to one O(13), one O(14), one O(7), and one O(9) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra, corners with two equivalent Li(5)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid,  a cornercorner with one Li(8)O4 trigonal pyramid,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Co(3)O4 tetrahedra. The Li(4)-O(13) bond length is 2.15 Å. The Li(4)-O(14) bond length is 1.99 Å. The Li(4)-O(7) bond length is 1.92 Å. The Li(4)-O(9) bond length is 1.98 Å. In the fifth Li site, Li(5) is bonded to one O(10), one O(13), one O(14), and one O(8) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra, corners with two equivalent Li(4)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid,  a cornercorner with one Li(8)O4 trigonal pyramid,  an edgeedge with one Na(7)O6 octahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Co(3)O4 tetrahedra. The Li(5)-O(10) bond length is 2.03 Å. The Li(5)-O(13) bond length is 2.01 Å. The Li(5)-O(14) bond length is 1.94 Å. The Li(5)-O(8) bond length is 1.97 Å. In the sixth Li site, Li(6) is bonded to one O(1), one O(11), one O(12), and one O(15) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, corners with two equivalent Li(7)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. The Li(6)-O(1) bond length is 1.95 Å. The Li(6)-O(11) bond length is 2.08 Å. The Li(6)-O(12) bond length is 2.08 Å. The Li(6)-O(15) bond length is 1.93 Å. In the seventh Li site, Li(7) is bonded to one O(11), one O(12), one O(16), and one O(2) atom to form LiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, corners with two equivalent Li(6)O4 tetrahedra,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. The Li(7)-O(11) bond length is 2.04 Å. The Li(7)-O(12) bond length is 2.07 Å. The Li(7)-O(16) bond length is 1.91 Å. The Li(7)-O(2) bond length is 1.94 Å. In the eighth Li site, Li(8) is bonded to one O(1), one O(11), one O(13), and one O(2) atom to form distorted LiO4 trigonal pyramids that share corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, corners with two equivalent Co(1)O4 tetrahedra,  an edgeedge with one Li(6)O4 tetrahedra,  an edgeedge with one Li(7)O4 tetrahedra, and  an edgeedge with one Co(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 75-76°. The Li(8)-O(1) bond length is 1.93 Å. The Li(8)-O(11) bond length is 2.02 Å. The Li(8)-O(13) bond length is 2.04 Å. The Li(8)-O(2) bond length is 1.93 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra, corners with two equivalent Li(8)O4 trigonal pyramids,  an edgeedge with one Na(7)O6 octahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The Co(1)-O(1) bond length is 1.83 Å. The Co(1)-O(2) bond length is 1.81 Å. The Co(1)-O(3) bond length is 1.83 Å. The Co(1)-O(5) bond length is 1.79 Å. In the second Co site, Co(2) is bonded to one O(4), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one Li(5)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The Co(2)-O(4) bond length is 1.81 Å. The Co(2)-O(6) bond length is 1.76 Å. The Co(2)-O(7) bond length is 1.84 Å. The Co(2)-O(8) bond length is 1.89 Å. In the third Co site, Co(3) is bonded to one O(10), one O(11), one O(13), and one O(9) atom to form CoO4 tetrahedra that share corners with two equivalent Na(7)O6 octahedra,  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(6)O4 tetrahedra,  a cornercorner with one Li(7)O4 tetrahedra, corners with two equivalent Li(2)O4 trigonal pyramids,  an edgeedge with one Li(4)O4 tetrahedra,  an edgeedge with one Li(5)O4 tetrahedra, and  an edgeedge with one Li(8)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 77-82°. The Co(3)-O(10) bond length is 1.81 Å. The Co(3)-O(11) bond length is 1.82 Å. The Co(3)-O(13) bond length is 1.82 Å. The Co(3)-O(9) bond length is 1.78 Å. In the fourth Co site, Co(4) is bonded in a 4-coordinate geometry to one O(12), one O(14), one O(15), and one O(16) atom. The Co(4)-O(12) bond length is 1.87 Å. The Co(4)-O(14) bond length is 1.86 Å. The Co(4)-O(15) bond length is 1.73 Å. The Co(4)-O(16) bond length is 1.72 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Na(1), one Na(3), one Na(7), one Li(6), one Li(8), and one Co(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Na(2), one Na(3), one Na(7), one Li(7), one Li(8), and one Co(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), one Li(1), one Li(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Li(1), and one Co(2) atom. In the fifth O site, O(5) is bonded in a distorted square pyramidal geometry to one Na(4), one Na(5), one Na(6), one Li(2), and one Co(1) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Na(3), one Na(5), one Na(6), and one Co(2) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Na(4), one Na(6), one Na(8), one Li(3), one Li(4), and one Co(2) atom. In the eighth O site, O(8) is bonded in a 7-coordinate geometry to one Na(4), one Na(5), one Na(8), one Li(1), one Li(3), one Li(5), and one Co(2) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Na(3), one Na(6), one Na(7), one Li(2), one Li(4), and one Co(3) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(5), one Na(7), one Li(1), one Li(2), one Li(5), and one Co(3) atom. In the eleventh O site, O(11) is bonded in a 7-coordinate geometry to one Na(5), one Na(6), one Na(8), one Li(6), one Li(7), one Li(8), and one Co(3) atom. In the twelfth O site, O(12) is bonded in a 7-coordinate geometry to one Na(5), one Na(6), one Na(7), one Li(3), one Li(6), one Li(7), and one Co(4) atom. In the thirteenth O site, O(13) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(8), one Li(4), one Li(5), one Li(8), and one Co(3) atom. In the fourteenth O site, O(14) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(7), one Li(3), one Li(4), one Li(5), and one Co(4) atom. In the fifteenth O site, O(15) is bonded in a 5-coordinate geometry to one Na(1), one Na(4), one Na(8), one Li(6), and one Co(4) atom. In the sixteenth O site, O(16) is bonded in a see-saw-like geometry to one Na(2), one Na(8), one Li(7), and one Co(4) atom.