CaVSi4O15 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(9), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. V(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(2)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. There are nine inequivalent O sites. In the first O site, O(3) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one V(1) atom. In the fifth O site, O(7) is bonded in a water-like geometry to one Ca(1) and one O(8) atom. In the sixth O site, O(8) is bonded in a water-like geometry to two equivalent O(7) atoms. In the seventh O site, O(9) is bonded in a single-bond geometry to one Ca(1) atom. In the eighth O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one V(1), and one Si(1) atom. In the ninth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one Si(2) atom.
CaVSi4O15 crystallizes in the orthorhombic Cmc2_1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(9), two equivalent O(1), two equivalent O(2), and two equivalent O(7) atoms. The Ca(1)-O(9) bond length is 2.27 Å. Both Ca(1)-O(1) bond lengths are 2.40 Å. Both Ca(1)-O(2) bond lengths are 2.40 Å. Both Ca(1)-O(7) bond lengths are 2.43 Å. V(1) is bonded to one O(6), two equivalent O(1), and two equivalent O(2) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. The V(1)-O(6) bond length is 1.61 Å. Both V(1)-O(1) bond lengths are 1.91 Å. Both V(1)-O(2) bond lengths are 1.92 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(2)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(3) bond length is 1.62 Å. The Si(1)-O(4) bond length is 1.63 Å. The Si(1)-O(5) bond length is 1.63 Å. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O4 tetrahedra and  a cornercorner with one V(1)O5 trigonal bipyramid. The Si(2)-O(2) bond length is 1.65 Å. The Si(2)-O(3) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.63 Å. The Si(2)-O(5) bond length is 1.63 Å. There are nine inequivalent O sites. In the first O site, O(3) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one V(1) atom. In the fifth O site, O(7) is bonded in a water-like geometry to one Ca(1) and one O(8) atom. The O(7)-O(8) bond length is 1.33 Å. In the sixth O site, O(8) is bonded in a water-like geometry to two equivalent O(7) atoms. In the seventh O site, O(9) is bonded in a single-bond geometry to one Ca(1) atom. In the eighth O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one V(1), and one Si(1) atom. In the ninth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one Si(2) atom.