Ca7Si6CH4O23 crystallizes in the monoclinic Cm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), two equivalent O(1), two equivalent O(11), and two equivalent O(9) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(5), one O(6), one O(8), and one O(9) atom. In the third Ca site, Ca(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form distorted CaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(14), one O(4), one O(5), and one O(6) atom. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-58°. In the second Si site, Si(2) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 62-63°. In the third Si site, Si(3) is bonded to one O(10), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-59°. C(1) is bonded in a trigonal planar geometry to one O(12) and two equivalent O(11) atoms. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(13) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(13) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) and one O(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Si(1) and one H(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(3), one Ca(4), and one Si(1) atom. In the fifth O site, O(5) is bonded to one Ca(2), one Ca(3), one Ca(4), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si trigonal pyramids. In the sixth O site, O(6) is bonded to one Ca(2), one Ca(3), one Ca(4), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Si(3) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and two equivalent Si(3) atoms. In the eleventh O site, O(11) is bonded in a 1-coordinate geometry to one Ca(1), one Ca(2), one Ca(4), and one C(1) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Ca(1), two equivalent Ca(2), and one C(1) atom. In the thirteenth O site, O(13) is bonded in a water-like geometry to two equivalent Ca(2), one H(1), and one H(2) atom. In the fourteenth O site, O(14) is bonded in a water-like geometry to two equivalent Ca(4), one H(3), and one H(4) atom.
Ca7Si6CH4O23 crystallizes in the monoclinic Cm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), two equivalent O(1), two equivalent O(11), and two equivalent O(9) atoms. The Ca(1)-O(10) bond length is 2.74 Å. The Ca(1)-O(12) bond length is 2.49 Å. Both Ca(1)-O(1) bond lengths are 2.39 Å. Both Ca(1)-O(11) bond lengths are 2.75 Å. Both Ca(1)-O(9) bond lengths are 2.41 Å. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(5), one O(6), one O(8), and one O(9) atom. The Ca(2)-O(11) bond length is 2.79 Å. The Ca(2)-O(12) bond length is 2.48 Å. The Ca(2)-O(13) bond length is 2.54 Å. The Ca(2)-O(5) bond length is 2.32 Å. The Ca(2)-O(6) bond length is 2.50 Å. The Ca(2)-O(8) bond length is 2.32 Å. The Ca(2)-O(9) bond length is 2.45 Å. In the third Ca site, Ca(3) is bonded to one O(1), one O(4), one O(5), one O(6), one O(8), and one O(9) atom to form distorted CaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Ca(3)-O(1) bond length is 2.43 Å. The Ca(3)-O(4) bond length is 2.41 Å. The Ca(3)-O(5) bond length is 2.46 Å. The Ca(3)-O(6) bond length is 2.49 Å. The Ca(3)-O(8) bond length is 2.41 Å. The Ca(3)-O(9) bond length is 2.41 Å. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(14), one O(4), one O(5), and one O(6) atom. The Ca(4)-O(1) bond length is 2.50 Å. The Ca(4)-O(11) bond length is 2.38 Å. The Ca(4)-O(14) bond length is 2.50 Å. The Ca(4)-O(4) bond length is 2.31 Å. The Ca(4)-O(5) bond length is 2.46 Å. The Ca(4)-O(6) bond length is 2.30 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-58°. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(2) bond length is 1.68 Å. The Si(1)-O(3) bond length is 1.66 Å. The Si(1)-O(4) bond length is 1.61 Å. In the second Si site, Si(2) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 62-63°. The Si(2)-O(3) bond length is 1.65 Å. The Si(2)-O(5) bond length is 1.63 Å. The Si(2)-O(6) bond length is 1.62 Å. The Si(2)-O(7) bond length is 1.65 Å. In the third Si site, Si(3) is bonded to one O(10), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-59°. The Si(3)-O(10) bond length is 1.70 Å. The Si(3)-O(7) bond length is 1.65 Å. The Si(3)-O(8) bond length is 1.61 Å. The Si(3)-O(9) bond length is 1.63 Å. C(1) is bonded in a trigonal planar geometry to one O(12) and two equivalent O(11) atoms. The C(1)-O(12) bond length is 1.30 Å. Both C(1)-O(11) bond lengths are 1.30 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(13) atom. The H(1)-O(13) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(13) atom. The H(2)-O(13) bond length is 0.98 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(14) and one O(2) atom. The H(3)-O(14) bond length is 1.00 Å. The H(3)-O(2) bond length is 1.71 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(14) atom. The H(4)-O(14) bond length is 0.98 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Si(1) and one H(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(3), one Ca(4), and one Si(1) atom. In the fifth O site, O(5) is bonded to one Ca(2), one Ca(3), one Ca(4), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si trigonal pyramids. In the sixth O site, O(6) is bonded to one Ca(2), one Ca(3), one Ca(4), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Si(3) atom. In the ninth O site, O(9) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Si(3) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and two equivalent Si(3) atoms. In the eleventh O site, O(11) is bonded in a 1-coordinate geometry to one Ca(1), one Ca(2), one Ca(4), and one C(1) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Ca(1), two equivalent Ca(2), and one C(1) atom. In the thirteenth O site, O(13) is bonded in a water-like geometry to two equivalent Ca(2), one H(1), and one H(2) atom. In the fourteenth O site, O(14) is bonded in a water-like geometry to two equivalent Ca(4), one H(3), and one H(4) atom.