Cs2CaV2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to one O(2), one O(4), one O(7), two equivalent O(1), two equivalent O(5), and three equivalent O(3) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to one O(1), one O(2), one O(5), two equivalent O(4), two equivalent O(7), and three equivalent O(6) atoms. Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form CaO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-33°. In the second V site, V(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-40°. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cs(1), two equivalent Cs(2), one V(1), and one V(2) atom. In the second O site, O(5) is bonded in a 2-coordinate geometry to one Cs(2), two equivalent Cs(1), one Ca(1), and one V(2) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to three equivalent Cs(2), one Ca(1), and one V(2) atom. In the fourth O site, O(7) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Ca(1), and one V(2) atom. In the fifth O site, O(1) is bonded in a 2-coordinate geometry to one Cs(2), two equivalent Cs(1), one Ca(1), and one V(1) atom. In the sixth O site, O(2) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), one Ca(1), and one V(1) atom. In the seventh O site, O(3) is bonded in a 2-coordinate geometry to three equivalent Cs(1), one Ca(1), and one V(1) atom.
Cs2CaV2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to one O(2), one O(4), one O(7), two equivalent O(1), two equivalent O(5), and three equivalent O(3) atoms. The Cs(1)-O(2) bond length is 3.17 Å. The Cs(1)-O(4) bond length is 3.64 Å. The Cs(1)-O(7) bond length is 3.27 Å. There is one shorter (3.39 Å) and one longer (3.54 Å) Cs(1)-O(1) bond length. There is one shorter (3.17 Å) and one longer (3.39 Å) Cs(1)-O(5) bond length. There are a spread of Cs(1)-O(3) bond distances ranging from 3.15-3.59 Å. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to one O(1), one O(2), one O(5), two equivalent O(4), two equivalent O(7), and three equivalent O(6) atoms. The Cs(2)-O(1) bond length is 3.35 Å. The Cs(2)-O(2) bond length is 3.27 Å. The Cs(2)-O(5) bond length is 3.13 Å. There is one shorter (3.30 Å) and one longer (3.34 Å) Cs(2)-O(4) bond length. There is one shorter (3.28 Å) and one longer (3.69 Å) Cs(2)-O(7) bond length. There are a spread of Cs(2)-O(6) bond distances ranging from 3.18-3.50 Å. Ca(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form CaO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra and corners with three equivalent V(2)O4 tetrahedra. The Ca(1)-O(1) bond length is 2.39 Å. The Ca(1)-O(2) bond length is 2.36 Å. The Ca(1)-O(3) bond length is 2.36 Å. The Ca(1)-O(5) bond length is 2.42 Å. The Ca(1)-O(6) bond length is 2.41 Å. The Ca(1)-O(7) bond length is 2.37 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-33°. The V(1)-O(1) bond length is 1.71 Å. The V(1)-O(2) bond length is 1.72 Å. The V(1)-O(3) bond length is 1.73 Å. The V(1)-O(4) bond length is 1.84 Å. In the second V site, V(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Ca(1)O6 octahedra and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-40°. The V(2)-O(4) bond length is 1.84 Å. The V(2)-O(5) bond length is 1.73 Å. The V(2)-O(6) bond length is 1.72 Å. The V(2)-O(7) bond length is 1.72 Å. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cs(1), two equivalent Cs(2), one V(1), and one V(2) atom. In the second O site, O(5) is bonded in a 2-coordinate geometry to one Cs(2), two equivalent Cs(1), one Ca(1), and one V(2) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to three equivalent Cs(2), one Ca(1), and one V(2) atom. In the fourth O site, O(7) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Ca(1), and one V(2) atom. In the fifth O site, O(1) is bonded in a 2-coordinate geometry to one Cs(2), two equivalent Cs(1), one Ca(1), and one V(1) atom. In the sixth O site, O(2) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), one Ca(1), and one V(1) atom. In the seventh O site, O(3) is bonded in a 2-coordinate geometry to three equivalent Cs(1), one Ca(1), and one V(1) atom.