Ca2V3O8 crystallizes in the triclinic P1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(11), one O(14), one O(15), one O(5), one O(8), and one O(9) atom to form distorted CaO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(3)O6 octahedra, corners with two equivalent V(4)O6 octahedra, corners with three equivalent Ca(4)O4 tetrahedra,  an edgeedge with one V(2)O6 octahedra,  an edgeedge with one V(5)O6 octahedra, and  an edgeedge with one V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the second Ca site, Ca(2) is bonded to one O(10), one O(12), one O(13), one O(16), one O(6), and one O(7) atom to form distorted CaO6 octahedra that share corners with two equivalent V(2)O6 octahedra, corners with two equivalent V(5)O6 octahedra, corners with two equivalent V(6)O6 octahedra, corners with three equivalent Ca(3)O4 tetrahedra,  an edgeedge with one V(1)O6 octahedra,  an edgeedge with one V(3)O6 octahedra, and  an edgeedge with one V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the third Ca site, Ca(3) is bonded to one O(12), one O(13), one O(16), and one O(4) atom to form CaO4 tetrahedra that share  a cornercorner with one V(2)O6 octahedra,  a cornercorner with one V(5)O6 octahedra,  a cornercorner with one V(6)O6 octahedra, corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(3)O6 octahedra, corners with two equivalent V(4)O6 octahedra, and corners with three equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-75°. In the fourth Ca site, Ca(4) is bonded to one O(11), one O(14), one O(15), and one O(3) atom to form CaO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(3)O6 octahedra,  a cornercorner with one V(4)O6 octahedra, corners with two equivalent V(2)O6 octahedra, corners with two equivalent V(5)O6 octahedra, corners with two equivalent V(6)O6 octahedra, and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-75°. There are six inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(12), one O(16), one O(3), one O(5), and one O(9) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(3)O6 octahedra, and edges with two equivalent V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the second V site, V(2) is bonded to one O(10), one O(11), one O(15), one O(2), one O(4), and one O(6) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(5)O6 octahedra, and edges with two equivalent V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the third V site, V(3) is bonded to one O(1), one O(12), one O(13), one O(3), one O(8), and one O(9) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(1)O6 octahedra, and edges with two equivalent V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the fourth V site, V(4) is bonded to one O(1), one O(13), one O(16), one O(3), one O(5), and one O(8) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(1)O6 octahedra, and edges with two equivalent V(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the fifth V site, V(5) is bonded to one O(14), one O(15), one O(2), one O(4), one O(6), and one O(7) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(2)O6 octahedra, and edges with two equivalent V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. In the sixth V site, V(6) is bonded to one O(10), one O(11), one O(14), one O(2), one O(4), and one O(7) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(2)O6 octahedra, and edges with two equivalent V(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one V(1), one V(3), and one V(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one V(2), one V(5), and one V(6) atom. In the third O site, O(3) is bonded to one Ca(4), one V(1), one V(3), and one V(4) atom to form a mixture of distorted corner and edge-sharing OCaV3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(3), one V(2), one V(5), and one V(6) atom to form a mixture of distorted corner and edge-sharing OCaV3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one V(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(2), and one V(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(5), and one V(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(3), and one V(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one V(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(2), and one V(6) atom. In the eleventh O site, O(11) is bonded to one Ca(1), one Ca(4), one V(2), and one V(6) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(14)Ca2V2 tetrahedra,  a cornercorner with one O(15)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(14)Ca2V2 tetrahedra,  an edgeedge with one O(15)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the twelfth O site, O(12) is bonded to one Ca(2), one Ca(3), one V(1), and one V(3) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(13)Ca2V2 tetrahedra,  a cornercorner with one O(16)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(13)Ca2V2 tetrahedra,  an edgeedge with one O(16)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid. In the thirteenth O site, O(13) is bonded to one Ca(2), one Ca(3), one V(3), and one V(4) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(12)Ca2V2 tetrahedra,  a cornercorner with one O(16)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(12)Ca2V2 tetrahedra,  an edgeedge with one O(16)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Ca(1), one Ca(4), one V(5), and one V(6) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(11)Ca2V2 tetrahedra,  a cornercorner with one O(15)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(11)Ca2V2 tetrahedra,  an edgeedge with one O(15)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the fifteenth O site, O(15) is bonded to one Ca(1), one Ca(4), one V(2), and one V(5) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(11)Ca2V2 tetrahedra,  a cornercorner with one O(14)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(11)Ca2V2 tetrahedra,  an edgeedge with one O(14)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the sixteenth O site, O(16) is bonded to one Ca(2), one Ca(3), one V(1), and one V(4) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(12)Ca2V2 tetrahedra,  a cornercorner with one O(13)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(12)Ca2V2 tetrahedra,  an edgeedge with one O(13)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid.
Ca2V3O8 crystallizes in the triclinic P1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(11), one O(14), one O(15), one O(5), one O(8), and one O(9) atom to form distorted CaO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(3)O6 octahedra, corners with two equivalent V(4)O6 octahedra, corners with three equivalent Ca(4)O4 tetrahedra,  an edgeedge with one V(2)O6 octahedra,  an edgeedge with one V(5)O6 octahedra, and  an edgeedge with one V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The Ca(1)-O(11) bond length is 2.39 Å. The Ca(1)-O(14) bond length is 2.39 Å. The Ca(1)-O(15) bond length is 2.39 Å. The Ca(1)-O(5) bond length is 2.33 Å. The Ca(1)-O(8) bond length is 2.33 Å. The Ca(1)-O(9) bond length is 2.33 Å. In the second Ca site, Ca(2) is bonded to one O(10), one O(12), one O(13), one O(16), one O(6), and one O(7) atom to form distorted CaO6 octahedra that share corners with two equivalent V(2)O6 octahedra, corners with two equivalent V(5)O6 octahedra, corners with two equivalent V(6)O6 octahedra, corners with three equivalent Ca(3)O4 tetrahedra,  an edgeedge with one V(1)O6 octahedra,  an edgeedge with one V(3)O6 octahedra, and  an edgeedge with one V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The Ca(2)-O(10) bond length is 2.33 Å. The Ca(2)-O(12) bond length is 2.39 Å. The Ca(2)-O(13) bond length is 2.39 Å. The Ca(2)-O(16) bond length is 2.39 Å. The Ca(2)-O(6) bond length is 2.32 Å. The Ca(2)-O(7) bond length is 2.33 Å. In the third Ca site, Ca(3) is bonded to one O(12), one O(13), one O(16), and one O(4) atom to form CaO4 tetrahedra that share  a cornercorner with one V(2)O6 octahedra,  a cornercorner with one V(5)O6 octahedra,  a cornercorner with one V(6)O6 octahedra, corners with two equivalent V(1)O6 octahedra, corners with two equivalent V(3)O6 octahedra, corners with two equivalent V(4)O6 octahedra, and corners with three equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-75°. The Ca(3)-O(12) bond length is 2.18 Å. The Ca(3)-O(13) bond length is 2.18 Å. The Ca(3)-O(16) bond length is 2.17 Å. The Ca(3)-O(4) bond length is 2.25 Å. In the fourth Ca site, Ca(4) is bonded to one O(11), one O(14), one O(15), and one O(3) atom to form CaO4 tetrahedra that share  a cornercorner with one V(1)O6 octahedra,  a cornercorner with one V(3)O6 octahedra,  a cornercorner with one V(4)O6 octahedra, corners with two equivalent V(2)O6 octahedra, corners with two equivalent V(5)O6 octahedra, corners with two equivalent V(6)O6 octahedra, and corners with three equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-75°. The Ca(4)-O(11) bond length is 2.17 Å. The Ca(4)-O(14) bond length is 2.18 Å. The Ca(4)-O(15) bond length is 2.17 Å. The Ca(4)-O(3) bond length is 2.26 Å. There are six inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(12), one O(16), one O(3), one O(5), and one O(9) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(3)O6 octahedra, and edges with two equivalent V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The V(1)-O(1) bond length is 2.01 Å. The V(1)-O(12) bond length is 1.93 Å. The V(1)-O(16) bond length is 2.06 Å. The V(1)-O(3) bond length is 2.07 Å. The V(1)-O(5) bond length is 2.02 Å. The V(1)-O(9) bond length is 1.84 Å. In the second V site, V(2) is bonded to one O(10), one O(11), one O(15), one O(2), one O(4), and one O(6) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(5)O6 octahedra, and edges with two equivalent V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The V(2)-O(10) bond length is 2.02 Å. The V(2)-O(11) bond length is 2.05 Å. The V(2)-O(15) bond length is 1.93 Å. The V(2)-O(2) bond length is 2.01 Å. The V(2)-O(4) bond length is 2.08 Å. The V(2)-O(6) bond length is 1.84 Å. In the third V site, V(3) is bonded to one O(1), one O(12), one O(13), one O(3), one O(8), and one O(9) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(1)O6 octahedra, and edges with two equivalent V(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The V(3)-O(1) bond length is 2.01 Å. The V(3)-O(12) bond length is 2.05 Å. The V(3)-O(13) bond length is 1.93 Å. The V(3)-O(3) bond length is 2.08 Å. The V(3)-O(8) bond length is 1.84 Å. The V(3)-O(9) bond length is 2.03 Å. In the fourth V site, V(4) is bonded to one O(1), one O(13), one O(16), one O(3), one O(5), and one O(8) atom to form VO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one Ca(4)O4 tetrahedra, corners with two equivalent Ca(3)O4 tetrahedra,  an edgeedge with one Ca(2)O6 octahedra, edges with two equivalent V(1)O6 octahedra, and edges with two equivalent V(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The V(4)-O(1) bond length is 2.01 Å. The V(4)-O(13) bond length is 2.05 Å. The V(4)-O(16) bond length is 1.93 Å. The V(4)-O(3) bond length is 2.08 Å. The V(4)-O(5) bond length is 1.85 Å. The V(4)-O(8) bond length is 2.03 Å. In the fifth V site, V(5) is bonded to one O(14), one O(15), one O(2), one O(4), one O(6), and one O(7) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(2)O6 octahedra, and edges with two equivalent V(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The V(5)-O(14) bond length is 1.93 Å. The V(5)-O(15) bond length is 2.06 Å. The V(5)-O(2) bond length is 2.01 Å. The V(5)-O(4) bond length is 2.08 Å. The V(5)-O(6) bond length is 2.02 Å. The V(5)-O(7) bond length is 1.84 Å. In the sixth V site, V(6) is bonded to one O(10), one O(11), one O(14), one O(2), one O(4), and one O(7) atom to form VO6 octahedra that share corners with two equivalent Ca(2)O6 octahedra,  a cornercorner with one Ca(3)O4 tetrahedra, corners with two equivalent Ca(4)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent V(2)O6 octahedra, and edges with two equivalent V(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. The V(6)-O(10) bond length is 1.84 Å. The V(6)-O(11) bond length is 1.93 Å. The V(6)-O(14) bond length is 2.05 Å. The V(6)-O(2) bond length is 2.01 Å. The V(6)-O(4) bond length is 2.08 Å. The V(6)-O(7) bond length is 2.02 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one V(1), one V(3), and one V(4) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one V(2), one V(5), and one V(6) atom. In the third O site, O(3) is bonded to one Ca(4), one V(1), one V(3), and one V(4) atom to form a mixture of distorted corner and edge-sharing OCaV3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(3), one V(2), one V(5), and one V(6) atom to form a mixture of distorted corner and edge-sharing OCaV3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one V(4) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(2), and one V(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(5), and one V(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(3), and one V(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ca(1), one V(1), and one V(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(2), one V(2), and one V(6) atom. In the eleventh O site, O(11) is bonded to one Ca(1), one Ca(4), one V(2), and one V(6) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(14)Ca2V2 tetrahedra,  a cornercorner with one O(15)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(14)Ca2V2 tetrahedra,  an edgeedge with one O(15)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the twelfth O site, O(12) is bonded to one Ca(2), one Ca(3), one V(1), and one V(3) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(13)Ca2V2 tetrahedra,  a cornercorner with one O(16)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(13)Ca2V2 tetrahedra,  an edgeedge with one O(16)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid. In the thirteenth O site, O(13) is bonded to one Ca(2), one Ca(3), one V(3), and one V(4) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(12)Ca2V2 tetrahedra,  a cornercorner with one O(16)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(12)Ca2V2 tetrahedra,  an edgeedge with one O(16)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Ca(1), one Ca(4), one V(5), and one V(6) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(11)Ca2V2 tetrahedra,  a cornercorner with one O(15)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(11)Ca2V2 tetrahedra,  an edgeedge with one O(15)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the fifteenth O site, O(15) is bonded to one Ca(1), one Ca(4), one V(2), and one V(5) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(11)Ca2V2 tetrahedra,  a cornercorner with one O(14)Ca2V2 tetrahedra,  a cornercorner with one O(3)CaV3 trigonal pyramid,  an edgeedge with one O(11)Ca2V2 tetrahedra,  an edgeedge with one O(14)Ca2V2 tetrahedra, and  an edgeedge with one O(4)CaV3 trigonal pyramid. In the sixteenth O site, O(16) is bonded to one Ca(2), one Ca(3), one V(1), and one V(4) atom to form OCa2V2 tetrahedra that share  a cornercorner with one O(12)Ca2V2 tetrahedra,  a cornercorner with one O(13)Ca2V2 tetrahedra,  a cornercorner with one O(4)CaV3 trigonal pyramid,  an edgeedge with one O(12)Ca2V2 tetrahedra,  an edgeedge with one O(13)Ca2V2 tetrahedra, and  an edgeedge with one O(3)CaV3 trigonal pyramid.