Ca9Si6(WO7)4 crystallizes in the triclinic P-1 space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(6), and two equivalent O(14) atoms. In the second Ca site, Ca(2) is bonded to one O(10), one O(13), one O(2), one O(7), and two equivalent O(5) atoms to form distorted CaO6 octahedra that share  a cornercorner with one Ca(4)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(5), one O(7), and two equivalent O(2) atoms. In the fourth Ca site, Ca(4) is bonded to one O(10), one O(11), one O(14), one O(3), and two equivalent O(6) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one W(1)O5 trigonal bipyramid,  an edgeedge with one Ca(4)O6 octahedra, and  an edgeedge with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 70°. In the fifth Ca site, Ca(5) is bonded in a linear geometry to two equivalent O(7) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(11), one O(12), one O(8), and two equivalent O(3) atoms to form WO5 trigonal bipyramids that share  a cornercorner with one Ca(4)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  an edgeedge with one Ca(4)O6 octahedra, and  an edgeedge with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 19°. In the second W site, W(2) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(12), one O(13), and one O(8) atom. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(4), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 66°. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with two equivalent Ca(4)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 43-60°. In the third Si site, Si(3) is bonded to one O(1), one O(14), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(4)O6 octahedra, corners with two equivalent Ca(2)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 54-68°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ca(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded to one Ca(2), two equivalent Ca(3), and one Si(2) atom to form distorted OCa3Si tetrahedra that share corners with two equivalent O(11)Ca3W tetrahedra,  a cornercorner with one O(6)Ca3Si trigonal pyramid, and  an edgeedge with one O(2)Ca3Si tetrahedra. In the third O site, O(3) is bonded in a T-shaped geometry to one Ca(4) and two equivalent W(1) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(3), two equivalent Ca(2), and one Si(3) atom. In the sixth O site, O(6) is bonded to one Ca(1), two equivalent Ca(4), and one Si(2) atom to form distorted OCa3Si trigonal pyramids that share  a cornercorner with one O(2)Ca3Si tetrahedra, corners with three equivalent O(11)Ca3W tetrahedra, and  an edgeedge with one O(6)Ca3Si trigonal pyramid. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Ca(5) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one W(1), one W(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(2), one Ca(4), and one W(2) atom. In the eleventh O site, O(11) is bonded to one Ca(1), one Ca(3), one Ca(4), and one W(1) atom to form distorted corner-sharing OCa3W tetrahedra. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Ca(1), one W(1), and one W(2) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(3), one W(2), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(4), two equivalent Ca(1), and one Si(3) atom.
Ca9Si6(WO7)4 crystallizes in the triclinic P-1 space group. There are five inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(6), and two equivalent O(14) atoms. The Ca(1)-O(1) bond length is 2.62 Å. The Ca(1)-O(10) bond length is 2.53 Å. The Ca(1)-O(11) bond length is 2.47 Å. The Ca(1)-O(12) bond length is 2.49 Å. The Ca(1)-O(6) bond length is 2.41 Å. There is one shorter (2.29 Å) and one longer (2.56 Å) Ca(1)-O(14) bond length. In the second Ca site, Ca(2) is bonded to one O(10), one O(13), one O(2), one O(7), and two equivalent O(5) atoms to form distorted CaO6 octahedra that share  a cornercorner with one Ca(4)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  an edgeedge with one Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles are 70°. The Ca(2)-O(10) bond length is 2.36 Å. The Ca(2)-O(13) bond length is 2.63 Å. The Ca(2)-O(2) bond length is 2.31 Å. The Ca(2)-O(7) bond length is 2.20 Å. There is one shorter (2.36 Å) and one longer (2.68 Å) Ca(2)-O(5) bond length. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(5), one O(7), and two equivalent O(2) atoms. The Ca(3)-O(11) bond length is 2.38 Å. The Ca(3)-O(13) bond length is 2.82 Å. The Ca(3)-O(5) bond length is 2.61 Å. The Ca(3)-O(7) bond length is 2.20 Å. There is one shorter (2.38 Å) and one longer (2.54 Å) Ca(3)-O(2) bond length. In the fourth Ca site, Ca(4) is bonded to one O(10), one O(11), one O(14), one O(3), and two equivalent O(6) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one W(1)O5 trigonal bipyramid,  an edgeedge with one Ca(4)O6 octahedra, and  an edgeedge with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 70°. The Ca(4)-O(10) bond length is 2.37 Å. The Ca(4)-O(11) bond length is 2.45 Å. The Ca(4)-O(14) bond length is 2.40 Å. The Ca(4)-O(3) bond length is 2.41 Å. There is one shorter (2.42 Å) and one longer (2.53 Å) Ca(4)-O(6) bond length. In the fifth Ca site, Ca(5) is bonded in a linear geometry to two equivalent O(7) atoms. Both Ca(5)-O(7) bond lengths are 2.16 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(11), one O(12), one O(8), and two equivalent O(3) atoms to form WO5 trigonal bipyramids that share  a cornercorner with one Ca(4)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  an edgeedge with one Ca(4)O6 octahedra, and  an edgeedge with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 19°. The W(1)-O(11) bond length is 2.00 Å. The W(1)-O(12) bond length is 1.97 Å. The W(1)-O(8) bond length is 2.25 Å. There is one shorter (1.93 Å) and one longer (2.12 Å) W(1)-O(3) bond length. In the second W site, W(2) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(12), one O(13), and one O(8) atom. The W(2)-O(10) bond length is 1.95 Å. The W(2)-O(12) bond length is 2.02 Å. The W(2)-O(13) bond length is 2.09 Å. The W(2)-O(8) bond length is 2.23 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(13), one O(4), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one W(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 66°. The Si(1)-O(13) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.63 Å. The Si(1)-O(8) bond length is 1.65 Å. The Si(1)-O(9) bond length is 1.63 Å. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with two equivalent Ca(4)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 43-60°. The Si(2)-O(1) bond length is 1.66 Å. The Si(2)-O(2) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.66 Å. The Si(2)-O(6) bond length is 1.63 Å. In the third Si site, Si(3) is bonded to one O(1), one O(14), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(4)O6 octahedra, corners with two equivalent Ca(2)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 54-68°. The Si(3)-O(1) bond length is 1.68 Å. The Si(3)-O(14) bond length is 1.63 Å. The Si(3)-O(5) bond length is 1.62 Å. The Si(3)-O(9) bond length is 1.66 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ca(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded to one Ca(2), two equivalent Ca(3), and one Si(2) atom to form distorted OCa3Si tetrahedra that share corners with two equivalent O(11)Ca3W tetrahedra,  a cornercorner with one O(6)Ca3Si trigonal pyramid, and  an edgeedge with one O(2)Ca3Si tetrahedra. In the third O site, O(3) is bonded in a T-shaped geometry to one Ca(4) and two equivalent W(1) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(3), two equivalent Ca(2), and one Si(3) atom. In the sixth O site, O(6) is bonded to one Ca(1), two equivalent Ca(4), and one Si(2) atom to form distorted OCa3Si trigonal pyramids that share  a cornercorner with one O(2)Ca3Si tetrahedra, corners with three equivalent O(11)Ca3W tetrahedra, and  an edgeedge with one O(6)Ca3Si trigonal pyramid. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Ca(5) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one W(1), one W(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(2), one Ca(4), and one W(2) atom. In the eleventh O site, O(11) is bonded to one Ca(1), one Ca(3), one Ca(4), and one W(1) atom to form distorted corner-sharing OCa3W tetrahedra. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Ca(1), one W(1), and one W(2) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(3), one W(2), and one Si(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Ca(4), two equivalent Ca(1), and one Si(3) atom.