Na3CoBAsO7 crystallizes in the triclinic P1 space group. There are twelve inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(21), one O(23), and one O(8) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(2), one O(22), one O(24), and one O(7) atom. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(25), one O(27), one O(3), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(26), one O(28), one O(4), and one O(5) atom. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(18), one O(22), and one O(5) atom. In the sixth Na site, Na(6) is bonded in a 6-coordinate geometry to one O(14), one O(17), one O(2), one O(21), one O(6), and one O(9) atom. In the seventh Na site, Na(7) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(17), one O(23), one O(24), one O(6), and one O(9) atom. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(18), one O(2), one O(23), and one O(5) atom. In the ninth Na site, Na(9) is bonded in a 6-coordinate geometry to one O(11), one O(15), one O(19), one O(26), one O(3), and one O(8) atom. In the tenth Na site, Na(10) is bonded in a 7-coordinate geometry to one O(12), one O(16), one O(20), one O(25), one O(26), one O(4), and one O(7) atom. In the eleventh Na site, Na(11) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(20), one O(28), one O(3), and one O(7) atom. In the twelfth Na site, Na(12) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(19), one O(27), one O(4), and one O(8) atom. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(16), one O(17), one O(21), one O(24), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(12), one O(14), one O(19), one O(26), one O(27), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. In the third Co site, Co(3) is bonded to one O(15), one O(18), one O(22), one O(23), one O(5), and one O(9) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. In the fourth Co site, Co(4) is bonded to one O(11), one O(13), one O(20), one O(25), one O(28), and one O(7) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(9) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(10), one O(4), and one O(6) atom. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(1), one O(11), and one O(7) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(12), one O(2), and one O(8) atom. There are four inequivalent As sites. In the first As site, As(1) is bonded to one O(13), one O(19), one O(21), and one O(23) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-51°. In the second As site, As(2) is bonded to one O(14), one O(20), one O(22), and one O(24) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-53°. In the third As site, As(3) is bonded to one O(15), one O(17), one O(25), and one O(27) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-54°. In the fourth As site, As(4) is bonded to one O(16), one O(18), one O(26), and one O(28) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(7), and one B(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), one Na(6), one Na(8), and one B(4) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(11), one Na(3), one Na(9), and one B(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(10), one Na(12), one Na(4), and one B(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(4), one Na(5), one Na(8), one Co(3), and one B(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal bipyramidal geometry to one Na(3), one Na(6), one Na(7), one Co(1), and one B(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(10), one Na(11), one Na(2), one Co(4), and one B(3) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(1), one Na(12), one Na(9), one Co(2), and one B(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(6), one Na(7), one Co(3), and one B(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Co(1), and one B(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(12), one Na(9), one Co(4), and one B(3) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(10), one Na(11), one Na(2), one Co(2), and one B(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Na(5), one Na(7), one Co(4), and one As(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(6), one Na(8), one Co(2), and one As(2) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Na(11), one Na(9), one Co(3), and one As(3) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(10), one Na(12), one Co(1), and one As(4) atom. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Na(6), one Na(7), one Co(1), and one As(3) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Na(5), one Na(8), one Co(3), and one As(4) atom. In the nineteenth O site, O(19) is bonded in a rectangular see-saw-like geometry to one Na(12), one Na(9), one Co(2), and one As(1) atom. In the twentieth O site, O(20) is bonded in a rectangular see-saw-like geometry to one Na(10), one Na(11), one Co(4), and one As(2) atom. In the twenty-first O site, O(21) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one Co(1), and one As(1) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Na(2), one Na(5), one Co(3), and one As(2) atom. In the twenty-third O site, O(23) is bonded in a 5-coordinate geometry to one Na(1), one Na(7), one Na(8), one Co(3), and one As(1) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(2), one Na(7), one Co(1), and one As(2) atom. In the twenty-fifth O site, O(25) is bonded in a 4-coordinate geometry to one Na(10), one Na(3), one Co(4), and one As(3) atom. In the twenty-sixth O site, O(26) is bonded in a 4-coordinate geometry to one Na(10), one Na(4), one Na(9), one Co(2), and one As(4) atom. In the twenty-seventh O site, O(27) is bonded in a 4-coordinate geometry to one Na(12), one Na(3), one Co(2), and one As(3) atom. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Na(11), one Na(4), one Co(4), and one As(4) atom.
Na3CoBAsO7 crystallizes in the triclinic P1 space group. There are twelve inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one O(1), one O(21), one O(23), and one O(8) atom. The Na(1)-O(1) bond length is 2.40 Å. The Na(1)-O(21) bond length is 2.48 Å. The Na(1)-O(23) bond length is 2.49 Å. The Na(1)-O(8) bond length is 2.31 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(2), one O(22), one O(24), and one O(7) atom. The Na(2)-O(1) bond length is 2.94 Å. The Na(2)-O(12) bond length is 2.81 Å. The Na(2)-O(2) bond length is 2.36 Å. The Na(2)-O(22) bond length is 2.51 Å. The Na(2)-O(24) bond length is 2.52 Å. The Na(2)-O(7) bond length is 2.41 Å. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(25), one O(27), one O(3), and one O(6) atom. The Na(3)-O(25) bond length is 2.46 Å. The Na(3)-O(27) bond length is 2.51 Å. The Na(3)-O(3) bond length is 2.36 Å. The Na(3)-O(6) bond length is 2.30 Å. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(26), one O(28), one O(4), and one O(5) atom. The Na(4)-O(26) bond length is 2.51 Å. The Na(4)-O(28) bond length is 2.45 Å. The Na(4)-O(4) bond length is 2.36 Å. The Na(4)-O(5) bond length is 2.31 Å. In the fifth Na site, Na(5) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(18), one O(22), and one O(5) atom. The Na(5)-O(1) bond length is 2.33 Å. The Na(5)-O(10) bond length is 2.39 Å. The Na(5)-O(13) bond length is 2.78 Å. The Na(5)-O(18) bond length is 2.38 Å. The Na(5)-O(22) bond length is 2.45 Å. The Na(5)-O(5) bond length is 2.51 Å. In the sixth Na site, Na(6) is bonded in a 6-coordinate geometry to one O(14), one O(17), one O(2), one O(21), one O(6), and one O(9) atom. The Na(6)-O(14) bond length is 2.75 Å. The Na(6)-O(17) bond length is 2.36 Å. The Na(6)-O(2) bond length is 2.29 Å. The Na(6)-O(21) bond length is 2.50 Å. The Na(6)-O(6) bond length is 2.50 Å. The Na(6)-O(9) bond length is 2.40 Å. In the seventh Na site, Na(7) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(17), one O(23), one O(24), one O(6), and one O(9) atom. The Na(7)-O(1) bond length is 2.33 Å. The Na(7)-O(13) bond length is 2.81 Å. The Na(7)-O(17) bond length is 2.37 Å. The Na(7)-O(23) bond length is 2.93 Å. The Na(7)-O(24) bond length is 2.48 Å. The Na(7)-O(6) bond length is 2.48 Å. The Na(7)-O(9) bond length is 2.40 Å. In the eighth Na site, Na(8) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(18), one O(2), one O(23), and one O(5) atom. The Na(8)-O(10) bond length is 2.41 Å. The Na(8)-O(14) bond length is 2.78 Å. The Na(8)-O(18) bond length is 2.35 Å. The Na(8)-O(2) bond length is 2.29 Å. The Na(8)-O(23) bond length is 2.54 Å. The Na(8)-O(5) bond length is 2.47 Å. In the ninth Na site, Na(9) is bonded in a 6-coordinate geometry to one O(11), one O(15), one O(19), one O(26), one O(3), and one O(8) atom. The Na(9)-O(11) bond length is 2.37 Å. The Na(9)-O(15) bond length is 2.77 Å. The Na(9)-O(19) bond length is 2.36 Å. The Na(9)-O(26) bond length is 2.50 Å. The Na(9)-O(3) bond length is 2.31 Å. The Na(9)-O(8) bond length is 2.52 Å. In the tenth Na site, Na(10) is bonded in a 7-coordinate geometry to one O(12), one O(16), one O(20), one O(25), one O(26), one O(4), and one O(7) atom. The Na(10)-O(12) bond length is 2.39 Å. The Na(10)-O(16) bond length is 2.73 Å. The Na(10)-O(20) bond length is 2.36 Å. The Na(10)-O(25) bond length is 2.49 Å. The Na(10)-O(26) bond length is 2.95 Å. The Na(10)-O(4) bond length is 2.29 Å. The Na(10)-O(7) bond length is 2.53 Å. In the eleventh Na site, Na(11) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(20), one O(28), one O(3), and one O(7) atom. The Na(11)-O(12) bond length is 2.41 Å. The Na(11)-O(15) bond length is 2.67 Å. The Na(11)-O(20) bond length is 2.37 Å. The Na(11)-O(28) bond length is 2.47 Å. The Na(11)-O(3) bond length is 2.30 Å. The Na(11)-O(7) bond length is 2.56 Å. In the twelfth Na site, Na(12) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(19), one O(27), one O(4), and one O(8) atom. The Na(12)-O(11) bond length is 2.35 Å. The Na(12)-O(16) bond length is 2.71 Å. The Na(12)-O(19) bond length is 2.37 Å. The Na(12)-O(27) bond length is 2.47 Å. The Na(12)-O(4) bond length is 2.31 Å. The Na(12)-O(8) bond length is 2.53 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(16), one O(17), one O(21), one O(24), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. The Co(1)-O(10) bond length is 1.92 Å. The Co(1)-O(16) bond length is 2.04 Å. The Co(1)-O(17) bond length is 2.01 Å. The Co(1)-O(21) bond length is 2.10 Å. The Co(1)-O(24) bond length is 2.10 Å. The Co(1)-O(6) bond length is 2.15 Å. In the second Co site, Co(2) is bonded to one O(12), one O(14), one O(19), one O(26), one O(27), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. The Co(2)-O(12) bond length is 1.95 Å. The Co(2)-O(14) bond length is 2.05 Å. The Co(2)-O(19) bond length is 2.01 Å. The Co(2)-O(26) bond length is 2.07 Å. The Co(2)-O(27) bond length is 2.05 Å. The Co(2)-O(8) bond length is 2.13 Å. In the third Co site, Co(3) is bonded to one O(15), one O(18), one O(22), one O(23), one O(5), and one O(9) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. The Co(3)-O(15) bond length is 2.04 Å. The Co(3)-O(18) bond length is 2.00 Å. The Co(3)-O(22) bond length is 2.10 Å. The Co(3)-O(23) bond length is 2.10 Å. The Co(3)-O(5) bond length is 2.17 Å. The Co(3)-O(9) bond length is 1.91 Å. In the fourth Co site, Co(4) is bonded to one O(11), one O(13), one O(20), one O(25), one O(28), and one O(7) atom to form CoO6 octahedra that share  a cornercorner with one As(1)O4 tetrahedra,  a cornercorner with one As(2)O4 tetrahedra,  a cornercorner with one As(3)O4 tetrahedra, and  a cornercorner with one As(4)O4 tetrahedra. The Co(4)-O(11) bond length is 1.93 Å. The Co(4)-O(13) bond length is 2.03 Å. The Co(4)-O(20) bond length is 1.96 Å. The Co(4)-O(25) bond length is 2.15 Å. The Co(4)-O(28) bond length is 2.14 Å. The Co(4)-O(7) bond length is 1.96 Å. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(3), one O(5), and one O(9) atom. The B(1)-O(3) bond length is 1.35 Å. The B(1)-O(5) bond length is 1.39 Å. The B(1)-O(9) bond length is 1.43 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(10), one O(4), and one O(6) atom. The B(2)-O(10) bond length is 1.43 Å. The B(2)-O(4) bond length is 1.35 Å. The B(2)-O(6) bond length is 1.39 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(1), one O(11), and one O(7) atom. The B(3)-O(1) bond length is 1.34 Å. The B(3)-O(11) bond length is 1.40 Å. The B(3)-O(7) bond length is 1.40 Å. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(12), one O(2), and one O(8) atom. The B(4)-O(12) bond length is 1.42 Å. The B(4)-O(2) bond length is 1.35 Å. The B(4)-O(8) bond length is 1.39 Å. There are four inequivalent As sites. In the first As site, As(1) is bonded to one O(13), one O(19), one O(21), and one O(23) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-51°. The As(1)-O(13) bond length is 1.74 Å. The As(1)-O(19) bond length is 1.71 Å. The As(1)-O(21) bond length is 1.73 Å. The As(1)-O(23) bond length is 1.73 Å. In the second As site, As(2) is bonded to one O(14), one O(20), one O(22), and one O(24) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-53°. The As(2)-O(14) bond length is 1.73 Å. The As(2)-O(20) bond length is 1.72 Å. The As(2)-O(22) bond length is 1.72 Å. The As(2)-O(24) bond length is 1.72 Å. In the third As site, As(3) is bonded to one O(15), one O(17), one O(25), and one O(27) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-54°. The As(3)-O(15) bond length is 1.74 Å. The As(3)-O(17) bond length is 1.72 Å. The As(3)-O(25) bond length is 1.71 Å. The As(3)-O(27) bond length is 1.73 Å. In the fourth As site, As(4) is bonded to one O(16), one O(18), one O(26), and one O(28) atom to form AsO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, and  a cornercorner with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. The As(4)-O(16) bond length is 1.74 Å. The As(4)-O(18) bond length is 1.72 Å. The As(4)-O(26) bond length is 1.73 Å. The As(4)-O(28) bond length is 1.72 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Na(5), one Na(7), and one B(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(2), one Na(6), one Na(8), and one B(4) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(11), one Na(3), one Na(9), and one B(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(10), one Na(12), one Na(4), and one B(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Na(4), one Na(5), one Na(8), one Co(3), and one B(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal bipyramidal geometry to one Na(3), one Na(6), one Na(7), one Co(1), and one B(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Na(10), one Na(11), one Na(2), one Co(4), and one B(3) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Na(1), one Na(12), one Na(9), one Co(2), and one B(4) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(6), one Na(7), one Co(3), and one B(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(5), one Na(8), one Co(1), and one B(2) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Na(12), one Na(9), one Co(4), and one B(3) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(10), one Na(11), one Na(2), one Co(2), and one B(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Na(5), one Na(7), one Co(4), and one As(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Na(6), one Na(8), one Co(2), and one As(2) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Na(11), one Na(9), one Co(3), and one As(3) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Na(10), one Na(12), one Co(1), and one As(4) atom. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Na(6), one Na(7), one Co(1), and one As(3) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Na(5), one Na(8), one Co(3), and one As(4) atom. In the nineteenth O site, O(19) is bonded in a rectangular see-saw-like geometry to one Na(12), one Na(9), one Co(2), and one As(1) atom. In the twentieth O site, O(20) is bonded in a rectangular see-saw-like geometry to one Na(10), one Na(11), one Co(4), and one As(2) atom. In the twenty-first O site, O(21) is bonded in a 4-coordinate geometry to one Na(1), one Na(6), one Co(1), and one As(1) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Na(2), one Na(5), one Co(3), and one As(2) atom. In the twenty-third O site, O(23) is bonded in a 5-coordinate geometry to one Na(1), one Na(7), one Na(8), one Co(3), and one As(1) atom. In the twenty-fourth O site, O(24) is bonded in a 4-coordinate geometry to one Na(2), one Na(7), one Co(1), and one As(2) atom. In the twenty-fifth O site, O(25) is bonded in a 4-coordinate geometry to one Na(10), one Na(3), one Co(4), and one As(3) atom. In the twenty-sixth O site, O(26) is bonded in a 4-coordinate geometry to one Na(10), one Na(4), one Na(9), one Co(2), and one As(4) atom. In the twenty-seventh O site, O(27) is bonded in a 4-coordinate geometry to one Na(12), one Na(3), one Co(2), and one As(3) atom. In the twenty-eighth O site, O(28) is bonded in a 4-coordinate geometry to one Na(11), one Na(4), one Co(4), and one As(4) atom.