Ca3W7Si6O15 crystallizes in the triclinic P1 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to one W(5), one O(12), one O(13), one O(15), and one O(8) atom. In the second Ca site, Ca(2) is bonded in a distorted rectangular see-saw-like geometry to one W(3), one W(7), one O(11), one O(12), one O(13), and one O(5) atom. In the third Ca site, Ca(3) is bonded in a distorted see-saw-like geometry to one O(11), one O(12), one O(15), and one O(8) atom. There are seven inequivalent W sites. In the first W site, W(1) is bonded in a distorted single-bond geometry to one O(3) atom. In the second W site, W(2) is bonded in a distorted single-bond geometry to one W(5), one W(7), and one O(5) atom. In the third W site, W(3) is bonded in a 2-coordinate geometry to one Ca(2), one W(5), one W(7), and one O(7) atom. In the fourth W site, W(4) is bonded in a single-bond geometry to one W(5), one W(7), and one O(9) atom. In the fifth W site, W(5) is bonded in a 6-coordinate geometry to one Ca(1), one W(2), one W(3), one W(4), one W(6), and one W(7) atom. In the sixth W site, W(6) is bonded in a distorted single-bond geometry to one W(5) and one O(5) atom. In the seventh W site, W(7) is bonded in a 6-coordinate geometry to one Ca(2), one W(2), one W(3), one W(4), one W(5), and one O(6) atom. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(13), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(11), one O(14), one O(4), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(3), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(1), one O(10), one O(15), and one O(2) atom to form corner-sharing SiO4 tetrahedra. In the sixth Si site, Si(6) is bonded to one O(1), one O(12), one O(14), and one O(3) atom to form corner-sharing SiO4 tetrahedra. There are fifteen 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(1) and one Si(5) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Si(4), and one Si(6) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral geometry to one Ca(2), one W(2), one W(6), and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one W(7), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one W(3), one Si(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(3), and one Si(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one W(4), one Si(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(5) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(2) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(6) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(3), and one Si(5) atom.
Ca3W7Si6O15 crystallizes in the triclinic P1 space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to one W(5), one O(12), one O(13), one O(15), and one O(8) atom. The Ca(1)-W(5) bond length is 3.75 Å. The Ca(1)-O(12) bond length is 2.61 Å. The Ca(1)-O(13) bond length is 2.30 Å. The Ca(1)-O(15) bond length is 2.43 Å. The Ca(1)-O(8) bond length is 2.30 Å. In the second Ca site, Ca(2) is bonded in a distorted rectangular see-saw-like geometry to one W(3), one W(7), one O(11), one O(12), one O(13), and one O(5) atom. The Ca(2)-W(3) bond length is 3.26 Å. The Ca(2)-W(7) bond length is 3.28 Å. The Ca(2)-O(11) bond length is 2.30 Å. The Ca(2)-O(12) bond length is 2.36 Å. The Ca(2)-O(13) bond length is 2.29 Å. The Ca(2)-O(5) bond length is 2.45 Å. In the third Ca site, Ca(3) is bonded in a distorted see-saw-like geometry to one O(11), one O(12), one O(15), and one O(8) atom. The Ca(3)-O(11) bond length is 2.32 Å. The Ca(3)-O(12) bond length is 2.59 Å. The Ca(3)-O(15) bond length is 2.35 Å. The Ca(3)-O(8) bond length is 2.40 Å. There are seven inequivalent W sites. In the first W site, W(1) is bonded in a distorted single-bond geometry to one O(3) atom. The W(1)-O(3) bond length is 2.39 Å. In the second W site, W(2) is bonded in a distorted single-bond geometry to one W(5), one W(7), and one O(5) atom. The W(2)-W(5) bond length is 2.68 Å. The W(2)-W(7) bond length is 3.09 Å. The W(2)-O(5) bond length is 2.32 Å. In the third W site, W(3) is bonded in a 2-coordinate geometry to one Ca(2), one W(5), one W(7), and one O(7) atom. The W(3)-W(5) bond length is 2.76 Å. The W(3)-W(7) bond length is 3.08 Å. The W(3)-O(7) bond length is 2.74 Å. In the fourth W site, W(4) is bonded in a single-bond geometry to one W(5), one W(7), and one O(9) atom. The W(4)-W(5) bond length is 2.88 Å. The W(4)-W(7) bond length is 3.03 Å. The W(4)-O(9) bond length is 2.53 Å. In the fifth W site, W(5) is bonded in a 6-coordinate geometry to one Ca(1), one W(2), one W(3), one W(4), one W(6), and one W(7) atom. The W(5)-W(6) bond length is 2.79 Å. The W(5)-W(7) bond length is 2.74 Å. In the sixth W site, W(6) is bonded in a distorted single-bond geometry to one W(5) and one O(5) atom. The W(6)-O(5) bond length is 2.33 Å. In the seventh W site, W(7) is bonded in a 6-coordinate geometry to one Ca(2), one W(2), one W(3), one W(4), one W(5), and one O(6) atom. The W(7)-O(6) bond length is 3.01 Å. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. The Si(1)-O(2) bond length is 1.63 Å. The Si(1)-O(5) bond length is 1.64 Å. The Si(1)-O(7) bond length is 1.66 Å. The Si(1)-O(9) bond length is 1.68 Å. In the second Si site, Si(2) is bonded to one O(13), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. The Si(2)-O(13) bond length is 1.60 Å. The Si(2)-O(4) bond length is 1.64 Å. The Si(2)-O(6) bond length is 1.66 Å. The Si(2)-O(7) bond length is 1.68 Å. In the third Si site, Si(3) is bonded to one O(11), one O(14), one O(4), and one O(9) atom to form corner-sharing SiO4 tetrahedra. The Si(3)-O(11) bond length is 1.61 Å. The Si(3)-O(14) bond length is 1.64 Å. The Si(3)-O(4) bond length is 1.64 Å. The Si(3)-O(9) bond length is 1.70 Å. In the fourth Si site, Si(4) is bonded to one O(10), one O(3), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. The Si(4)-O(10) bond length is 1.63 Å. The Si(4)-O(3) bond length is 1.69 Å. The Si(4)-O(6) bond length is 1.66 Å. The Si(4)-O(8) bond length is 1.61 Å. In the fifth Si site, Si(5) is bonded to one O(1), one O(10), one O(15), and one O(2) atom to form corner-sharing SiO4 tetrahedra. The Si(5)-O(1) bond length is 1.66 Å. The Si(5)-O(10) bond length is 1.66 Å. The Si(5)-O(15) bond length is 1.62 Å. The Si(5)-O(2) bond length is 1.68 Å. In the sixth Si site, Si(6) is bonded to one O(1), one O(12), one O(14), and one O(3) atom to form corner-sharing SiO4 tetrahedra. The Si(6)-O(1) bond length is 1.63 Å. The Si(6)-O(12) bond length is 1.62 Å. The Si(6)-O(14) bond length is 1.64 Å. The Si(6)-O(3) bond length is 1.68 Å. There are fifteen 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(1) and one Si(5) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Si(4), and one Si(6) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral geometry to one Ca(2), one W(2), one W(6), and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one W(7), one Si(2), and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one W(3), one Si(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(3), and one Si(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one W(4), one Si(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(5) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ca(2), one Ca(3), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and one Si(6) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(2) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(6) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(3), and one Si(5) atom.