Na4Cr3Al(P2O7)4 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(14), one O(19), one O(25), and one O(8) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(13), one O(2), one O(20), one O(26), one O(7), and one O(9) atom. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(16), one O(17), one O(27), one O(3), and one O(6) atom. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(11), one O(15), one O(18), one O(28), one O(4), one O(5), and one O(9) atom. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(12), one O(16), one O(18), one O(23), one O(27), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(13), one O(19), one O(22), one O(26), one O(8), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one P(7)O4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(10), one O(14), one O(20), one O(21), one O(25), and one O(7) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. Al(1) is bonded to one O(11), one O(15), one O(17), one O(24), one O(28), and one O(6) atom to form AlO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(25), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-55°. In the second P site, P(2) is bonded to one O(10), one O(2), one O(26), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-55°. In the third P site, P(3) is bonded to one O(11), one O(27), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-53°. In the fourth P site, P(4) is bonded to one O(12), one O(28), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-54°. In the fifth P site, P(5) is bonded to one O(1), one O(13), one O(17), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-51°. In the sixth P site, P(6) is bonded to one O(14), one O(18), one O(2), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-51°. In the seventh P site, P(7) is bonded to one O(15), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-47°. In the eighth P site, P(8) is bonded to one O(16), one O(20), one O(24), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-51°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(5) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one P(2), and one P(6) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(3), one P(3), and one P(7) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(4), one P(4), and one P(8) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(4), one Cr(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(3), one Al(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Cr(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(1), one Cr(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Na(4), one Cr(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Cr(3), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(4), one Al(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Cr(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Na(2), one Cr(2), and one P(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(3), and one P(6) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Na(4), one Al(1), and one P(7) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Na(3), one Cr(1), and one P(8) atom. In the seventeenth O site, O(17) is bonded in a 3-coordinate geometry to one Na(3), one Al(1), and one P(5) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Na(4), one Cr(1), and one P(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Na(1), one Cr(2), and one P(7) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Na(2), one Cr(3), and one P(8) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(3) and one P(5) atom. In the twenty-second O site, O(22) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one P(6) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Al(1) and one P(8) atom. In the twenty-fifth O site, O(25) is bonded in a 3-coordinate geometry to one Na(1), one Cr(3), and one P(1) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Na(2), one Cr(2), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a 3-coordinate geometry to one Na(3), one Cr(1), and one P(3) atom. In the twenty-eighth O site, O(28) is bonded in a 3-coordinate geometry to one Na(4), one Al(1), and one P(4) atom.
Na4Cr3Al(P2O7)4 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(14), one O(19), one O(25), and one O(8) atom. The Na(1)-O(1) bond length is 2.60 Å. The Na(1)-O(10) bond length is 2.47 Å. The Na(1)-O(14) bond length is 2.39 Å. The Na(1)-O(19) bond length is 2.65 Å. The Na(1)-O(25) bond length is 2.33 Å. The Na(1)-O(8) bond length is 2.68 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(13), one O(2), one O(20), one O(26), one O(7), and one O(9) atom. The Na(2)-O(13) bond length is 2.39 Å. The Na(2)-O(2) bond length is 2.57 Å. The Na(2)-O(20) bond length is 2.63 Å. The Na(2)-O(26) bond length is 2.33 Å. The Na(2)-O(7) bond length is 2.65 Å. The Na(2)-O(9) bond length is 2.45 Å. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(10), one O(12), one O(16), one O(17), one O(27), one O(3), and one O(6) atom. The Na(3)-O(10) bond length is 2.89 Å. The Na(3)-O(12) bond length is 2.45 Å. The Na(3)-O(16) bond length is 2.39 Å. The Na(3)-O(17) bond length is 2.68 Å. The Na(3)-O(27) bond length is 2.33 Å. The Na(3)-O(3) bond length is 2.57 Å. The Na(3)-O(6) bond length is 2.74 Å. In the fourth Na site, Na(4) is bonded in a 7-coordinate geometry to one O(11), one O(15), one O(18), one O(28), one O(4), one O(5), and one O(9) atom. The Na(4)-O(11) bond length is 2.47 Å. The Na(4)-O(15) bond length is 2.46 Å. The Na(4)-O(18) bond length is 2.63 Å. The Na(4)-O(28) bond length is 2.38 Å. The Na(4)-O(4) bond length is 2.54 Å. The Na(4)-O(5) bond length is 2.66 Å. The Na(4)-O(9) bond length is 2.92 Å. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(12), one O(16), one O(18), one O(23), one O(27), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The Cr(1)-O(12) bond length is 2.05 Å. The Cr(1)-O(16) bond length is 2.02 Å. The Cr(1)-O(18) bond length is 1.98 Å. The Cr(1)-O(23) bond length is 1.96 Å. The Cr(1)-O(27) bond length is 1.99 Å. The Cr(1)-O(5) bond length is 2.04 Å. In the second Cr site, Cr(2) is bonded to one O(13), one O(19), one O(22), one O(26), one O(8), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one P(7)O4 tetrahedra. The Cr(2)-O(13) bond length is 2.01 Å. The Cr(2)-O(19) bond length is 1.99 Å. The Cr(2)-O(22) bond length is 1.96 Å. The Cr(2)-O(26) bond length is 1.99 Å. The Cr(2)-O(8) bond length is 2.04 Å. The Cr(2)-O(9) bond length is 2.05 Å. In the third Cr site, Cr(3) is bonded to one O(10), one O(14), one O(20), one O(21), one O(25), and one O(7) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The Cr(3)-O(10) bond length is 2.08 Å. The Cr(3)-O(14) bond length is 2.01 Å. The Cr(3)-O(20) bond length is 2.01 Å. The Cr(3)-O(21) bond length is 1.98 Å. The Cr(3)-O(25) bond length is 2.00 Å. The Cr(3)-O(7) bond length is 2.07 Å. Al(1) is bonded to one O(11), one O(15), one O(17), one O(24), one O(28), and one O(6) atom to form AlO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The Al(1)-O(11) bond length is 1.98 Å. The Al(1)-O(15) bond length is 1.95 Å. The Al(1)-O(17) bond length is 1.91 Å. The Al(1)-O(24) bond length is 1.88 Å. The Al(1)-O(28) bond length is 1.91 Å. The Al(1)-O(6) bond length is 1.97 Å. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(25), one O(5), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-55°. The P(1)-O(1) bond length is 1.63 Å. The P(1)-O(25) bond length is 1.52 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(9) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(10), one O(2), one O(26), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-55°. The P(2)-O(10) bond length is 1.55 Å. The P(2)-O(2) bond length is 1.63 Å. The P(2)-O(26) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.53 Å. In the third P site, P(3) is bonded to one O(11), one O(27), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-53°. The P(3)-O(11) bond length is 1.54 Å. The P(3)-O(27) bond length is 1.52 Å. The P(3)-O(3) bond length is 1.63 Å. The P(3)-O(7) bond length is 1.53 Å. In the fourth P site, P(4) is bonded to one O(12), one O(28), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-54°. The P(4)-O(12) bond length is 1.54 Å. The P(4)-O(28) bond length is 1.52 Å. The P(4)-O(4) bond length is 1.64 Å. The P(4)-O(8) bond length is 1.53 Å. In the fifth P site, P(5) is bonded to one O(1), one O(13), one O(17), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-51°. The P(5)-O(1) bond length is 1.63 Å. The P(5)-O(13) bond length is 1.54 Å. The P(5)-O(17) bond length is 1.53 Å. The P(5)-O(21) bond length is 1.51 Å. In the sixth P site, P(6) is bonded to one O(14), one O(18), one O(2), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-51°. The P(6)-O(14) bond length is 1.54 Å. The P(6)-O(18) bond length is 1.53 Å. The P(6)-O(2) bond length is 1.62 Å. The P(6)-O(22) bond length is 1.51 Å. In the seventh P site, P(7) is bonded to one O(15), one O(19), one O(23), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-47°. The P(7)-O(15) bond length is 1.54 Å. The P(7)-O(19) bond length is 1.53 Å. The P(7)-O(23) bond length is 1.51 Å. The P(7)-O(3) bond length is 1.62 Å. In the eighth P site, P(8) is bonded to one O(16), one O(20), one O(24), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one Al(1)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-51°. The P(8)-O(16) bond length is 1.54 Å. The P(8)-O(20) bond length is 1.53 Å. The P(8)-O(24) bond length is 1.51 Å. The P(8)-O(4) bond length is 1.63 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one P(1), and one P(5) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(2), one P(2), and one P(6) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(3), one P(3), and one P(7) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(4), one P(4), and one P(8) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(4), one Cr(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Na(3), one Al(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Cr(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(1), one Cr(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Na(4), one Cr(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Cr(3), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(4), one Al(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Cr(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Na(2), one Cr(2), and one P(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Na(1), one Cr(3), and one P(6) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Na(4), one Al(1), and one P(7) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Na(3), one Cr(1), and one P(8) atom. In the seventeenth O site, O(17) is bonded in a 3-coordinate geometry to one Na(3), one Al(1), and one P(5) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Na(4), one Cr(1), and one P(6) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Na(1), one Cr(2), and one P(7) atom. In the twentieth O site, O(20) is bonded in a distorted trigonal planar geometry to one Na(2), one Cr(3), and one P(8) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(3) and one P(5) atom. In the twenty-second O site, O(22) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one P(6) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 150 degrees geometry to one Al(1) and one P(8) atom. In the twenty-fifth O site, O(25) is bonded in a 3-coordinate geometry to one Na(1), one Cr(3), and one P(1) atom. In the twenty-sixth O site, O(26) is bonded in a 3-coordinate geometry to one Na(2), one Cr(2), and one P(2) atom. In the twenty-seventh O site, O(27) is bonded in a 3-coordinate geometry to one Na(3), one Cr(1), and one P(3) atom. In the twenty-eighth O site, O(28) is bonded in a 3-coordinate geometry to one Na(4), one Al(1), and one P(4) atom.