Ba2CaV2(Si2O7)2 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(2), one O(3), one O(4), one O(7), and one O(9) atom. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(2), one O(3), and one O(8) atom. Ca(1) is bonded to one O(12), one O(14), one O(4), one O(6), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one Si(4)O4 tetrahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(5), one O(6), and one O(7) atom. In the second V site, V(2) is bonded to one O(1), one O(13), one O(3), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 65°. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(2), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 68°. In the third Si site, Si(3) is bonded to one O(13), one O(3), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the fourth Si site, Si(4) is bonded to one O(10), one O(14), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  an edgeedge with one Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 42°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one V(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one V(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one V(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), one V(1), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one V(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ca(1), one V(1), one Si(3), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one V(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(1), and one V(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Si(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Si(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ba(2), one Ca(1), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one V(2), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a distorted tetrahedral geometry to one Ba(1), one Ba(2), one Ca(1), and one Si(4) atom.
Ba2CaV2(Si2O7)2 crystallizes in the triclinic P1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(11), one O(13), one O(14), one O(2), one O(3), one O(4), one O(7), and one O(9) atom. The Ba(1)-O(1) bond length is 2.85 Å. The Ba(1)-O(11) bond length is 2.58 Å. The Ba(1)-O(13) bond length is 3.42 Å. The Ba(1)-O(14) bond length is 2.79 Å. The Ba(1)-O(2) bond length is 3.00 Å. The Ba(1)-O(3) bond length is 3.25 Å. The Ba(1)-O(4) bond length is 3.11 Å. The Ba(1)-O(7) bond length is 2.67 Å. The Ba(1)-O(9) bond length is 2.87 Å. In the second Ba site, Ba(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(2), one O(3), and one O(8) atom. The Ba(2)-O(11) bond length is 2.61 Å. The Ba(2)-O(12) bond length is 2.69 Å. The Ba(2)-O(13) bond length is 3.25 Å. The Ba(2)-O(14) bond length is 2.75 Å. The Ba(2)-O(2) bond length is 2.71 Å. The Ba(2)-O(3) bond length is 3.03 Å. The Ba(2)-O(8) bond length is 2.90 Å. Ca(1) is bonded to one O(12), one O(14), one O(4), one O(6), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one Si(4)O4 tetrahedra. The Ca(1)-O(12) bond length is 2.42 Å. The Ca(1)-O(14) bond length is 2.34 Å. The Ca(1)-O(4) bond length is 2.29 Å. The Ca(1)-O(6) bond length is 2.70 Å. The Ca(1)-O(7) bond length is 2.23 Å. The Ca(1)-O(8) bond length is 2.35 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(5), one O(6), and one O(7) atom. The V(1)-O(2) bond length is 2.04 Å. The V(1)-O(4) bond length is 2.17 Å. The V(1)-O(5) bond length is 2.14 Å. The V(1)-O(6) bond length is 2.12 Å. The V(1)-O(7) bond length is 1.79 Å. In the second V site, V(2) is bonded to one O(1), one O(13), one O(3), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 65°. The V(2)-O(1) bond length is 2.03 Å. The V(2)-O(13) bond length is 2.07 Å. The V(2)-O(3) bond length is 2.11 Å. The V(2)-O(8) bond length is 1.77 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(11) bond length is 1.58 Å. The Si(1)-O(5) bond length is 1.70 Å. The Si(1)-O(9) bond length is 1.69 Å. In the second Si site, Si(2) is bonded to one O(10), one O(12), one O(2), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 68°. The Si(2)-O(10) bond length is 1.63 Å. The Si(2)-O(12) bond length is 1.59 Å. The Si(2)-O(2) bond length is 1.65 Å. The Si(2)-O(5) bond length is 1.69 Å. In the third Si site, Si(3) is bonded to one O(13), one O(3), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. The Si(3)-O(13) bond length is 1.63 Å. The Si(3)-O(3) bond length is 1.62 Å. The Si(3)-O(6) bond length is 1.73 Å. The Si(3)-O(9) bond length is 1.68 Å. In the fourth Si site, Si(4) is bonded to one O(10), one O(14), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  an edgeedge with one Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 42°. The Si(4)-O(10) bond length is 1.62 Å. The Si(4)-O(14) bond length is 1.61 Å. The Si(4)-O(4) bond length is 1.63 Å. The Si(4)-O(6) bond length is 1.73 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one V(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one V(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Ba(2), one V(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), one V(1), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one V(1), one Si(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Ca(1), one V(1), one Si(3), and one Si(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(1), and one V(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(1), and one V(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Si(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Si(2) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ba(2), one Ca(1), and one Si(2) atom. In the thirteenth O site, O(13) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one V(2), and one Si(3) atom. In the fourteenth O site, O(14) is bonded in a distorted tetrahedral geometry to one Ba(1), one Ba(2), one Ca(1), and one Si(4) atom.