Ca2Al4Si8O33 crystallizes in the triclinic P1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(13), one O(14), one O(21), one O(23), one O(24), one O(29), and one O(30) atom. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(22), one O(25), one O(26), and one O(27) atom. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(13), one O(23), one O(3), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(10), one O(14), one O(24), and one O(4) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. In the third Al site, Al(3) is bonded to one O(15), one O(25), one O(5), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. In the fourth Al site, Al(4) is bonded to one O(16), one O(26), one O(6), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(13), one O(17), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(11), one O(14), one O(18), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(12), one O(15), one O(19), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(16), and one O(20) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(1), one O(17), one O(23), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. In the sixth Si site, Si(6) is bonded to one O(1), one O(18), one O(24), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. In the seventh Si site, Si(7) is bonded to one O(19), one O(2), one O(25), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. In the eighth Si site, Si(8) is bonded to one O(2), one O(20), one O(26), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. There are thirty-three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(5) and one Si(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(7) and one Si(8) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(8) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(7) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(3) and one Si(6) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Al(4) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Al(3) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Al(4) and one Si(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ca(2), one Al(3), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(4), and one Si(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(7) atom. In the twentieth O site, O(20) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a bent 120 degrees geometry to one Ca(1) and one O(33) atom. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one Ca(2) and one O(32) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(6) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(3), and one Si(7) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(4), and one Si(8) atom. In the twenty-seventh O site, O(27) is bonded in a water-like geometry to one Ca(2) and one O(28) atom. In the twenty-eighth O site, O(28) is bonded in a bent 120 degrees geometry to one O(27) and one O(31) atom. In the twenty-ninth O site, O(29) is bonded in a 2-coordinate geometry to one Ca(1) and one O(30) atom. In the thirtieth O site, O(30) is bonded in a distorted L-shaped geometry to one Ca(1) and one O(29) atom. In the thirty-first O site, O(31) is bonded in a single-bond geometry to one O(28) atom. In the thirty-second O site, O(32) is bonded in a single-bond geometry to one O(22) atom. In the thirty-third O site, O(33) is bonded in a single-bond geometry to one O(21) atom.
Ca2Al4Si8O33 crystallizes in the triclinic P1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(13), one O(14), one O(21), one O(23), one O(24), one O(29), and one O(30) atom. The Ca(1)-O(13) bond length is 2.29 Å. The Ca(1)-O(14) bond length is 2.29 Å. The Ca(1)-O(21) bond length is 2.89 Å. The Ca(1)-O(23) bond length is 2.30 Å. The Ca(1)-O(24) bond length is 2.30 Å. The Ca(1)-O(29) bond length is 2.71 Å. The Ca(1)-O(30) bond length is 2.68 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(15), one O(16), one O(22), one O(25), one O(26), and one O(27) atom. The Ca(2)-O(15) bond length is 2.32 Å. The Ca(2)-O(16) bond length is 2.33 Å. The Ca(2)-O(22) bond length is 2.88 Å. The Ca(2)-O(25) bond length is 2.30 Å. The Ca(2)-O(26) bond length is 2.32 Å. The Ca(2)-O(27) bond length is 2.50 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(13), one O(23), one O(3), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The Al(1)-O(13) bond length is 1.81 Å. The Al(1)-O(23) bond length is 1.80 Å. The Al(1)-O(3) bond length is 1.73 Å. The Al(1)-O(9) bond length is 1.73 Å. In the second Al site, Al(2) is bonded to one O(10), one O(14), one O(24), and one O(4) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The Al(2)-O(10) bond length is 1.74 Å. The Al(2)-O(14) bond length is 1.81 Å. The Al(2)-O(24) bond length is 1.80 Å. The Al(2)-O(4) bond length is 1.73 Å. In the third Al site, Al(3) is bonded to one O(15), one O(25), one O(5), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The Al(3)-O(15) bond length is 1.80 Å. The Al(3)-O(25) bond length is 1.80 Å. The Al(3)-O(5) bond length is 1.73 Å. The Al(3)-O(7) bond length is 1.73 Å. In the fourth Al site, Al(4) is bonded to one O(16), one O(26), one O(6), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The Al(4)-O(16) bond length is 1.81 Å. The Al(4)-O(26) bond length is 1.80 Å. The Al(4)-O(6) bond length is 1.73 Å. The Al(4)-O(8) bond length is 1.74 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(13), one O(17), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The Si(1)-O(11) bond length is 1.65 Å. The Si(1)-O(13) bond length is 1.65 Å. The Si(1)-O(17) bond length is 1.64 Å. The Si(1)-O(7) bond length is 1.61 Å. In the second Si site, Si(2) is bonded to one O(11), one O(14), one O(18), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The Si(2)-O(11) bond length is 1.65 Å. The Si(2)-O(14) bond length is 1.65 Å. The Si(2)-O(18) bond length is 1.64 Å. The Si(2)-O(8) bond length is 1.61 Å. In the third Si site, Si(3) is bonded to one O(12), one O(15), one O(19), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The Si(3)-O(12) bond length is 1.65 Å. The Si(3)-O(15) bond length is 1.65 Å. The Si(3)-O(19) bond length is 1.64 Å. The Si(3)-O(9) bond length is 1.61 Å. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(16), and one O(20) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The Si(4)-O(10) bond length is 1.61 Å. The Si(4)-O(12) bond length is 1.65 Å. The Si(4)-O(16) bond length is 1.65 Å. The Si(4)-O(20) bond length is 1.64 Å. In the fifth Si site, Si(5) is bonded to one O(1), one O(17), one O(23), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The Si(5)-O(1) bond length is 1.64 Å. The Si(5)-O(17) bond length is 1.64 Å. The Si(5)-O(23) bond length is 1.66 Å. The Si(5)-O(6) bond length is 1.60 Å. In the sixth Si site, Si(6) is bonded to one O(1), one O(18), one O(24), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The Si(6)-O(1) bond length is 1.64 Å. The Si(6)-O(18) bond length is 1.64 Å. The Si(6)-O(24) bond length is 1.66 Å. The Si(6)-O(5) bond length is 1.60 Å. In the seventh Si site, Si(7) is bonded to one O(19), one O(2), one O(25), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(8)O4 tetrahedra. The Si(7)-O(19) bond length is 1.64 Å. The Si(7)-O(2) bond length is 1.64 Å. The Si(7)-O(25) bond length is 1.66 Å. The Si(7)-O(4) bond length is 1.60 Å. In the eighth Si site, Si(8) is bonded to one O(2), one O(20), one O(26), and one O(3) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(7)O4 tetrahedra. The Si(8)-O(2) bond length is 1.64 Å. The Si(8)-O(20) bond length is 1.64 Å. The Si(8)-O(26) bond length is 1.66 Å. The Si(8)-O(3) bond length is 1.60 Å. There are thirty-three inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(5) and one Si(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(7) and one Si(8) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(8) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(7) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(3) and one Si(6) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Al(4) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Al(3) and one Si(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Al(4) and one Si(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(2) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ca(2), one Al(3), and one Si(3) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(4), and one Si(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(7) atom. In the twentieth O site, O(20) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(8) atom. In the twenty-first O site, O(21) is bonded in a bent 120 degrees geometry to one Ca(1) and one O(33) atom. The O(21)-O(33) bond length is 1.23 Å. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one Ca(2) and one O(32) atom. The O(22)-O(32) bond length is 1.23 Å. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(5) atom. In the twenty-fourth O site, O(24) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(6) atom. In the twenty-fifth O site, O(25) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(3), and one Si(7) atom. In the twenty-sixth O site, O(26) is bonded in a distorted trigonal planar geometry to one Ca(2), one Al(4), and one Si(8) atom. In the twenty-seventh O site, O(27) is bonded in a water-like geometry to one Ca(2) and one O(28) atom. The O(27)-O(28) bond length is 1.33 Å. In the twenty-eighth O site, O(28) is bonded in a bent 120 degrees geometry to one O(27) and one O(31) atom. The O(28)-O(31) bond length is 1.26 Å. In the twenty-ninth O site, O(29) is bonded in a 2-coordinate geometry to one Ca(1) and one O(30) atom. The O(29)-O(30) bond length is 1.24 Å. In the thirtieth O site, O(30) is bonded in a distorted L-shaped geometry to one Ca(1) and one O(29) atom. In the thirty-first O site, O(31) is bonded in a single-bond geometry to one O(28) atom. In the thirty-second O site, O(32) is bonded in a single-bond geometry to one O(22) atom. In the thirty-third O site, O(33) is bonded in a single-bond geometry to one O(21) atom.