Ba2VP2O11 crystallizes in the monoclinic P2_1 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(2), one O(6), one O(7), two equivalent O(1), two equivalent O(11), and two equivalent O(8) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(2), one O(4), one O(6), one O(8), one O(9), two equivalent O(10), two equivalent O(3), and two equivalent O(5) atoms. V(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted VO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one V(1)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(10), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent V(1)O5 trigonal bipyramids. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to two equivalent Ba(1) and one V(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one V(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Ba(2), one V(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one V(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(2), one V(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one Ba(2) and one P(2) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one P(2) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to two equivalent Ba(1) atoms.
Ba2VP2O11 crystallizes in the monoclinic P2_1 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(2), one O(6), one O(7), two equivalent O(1), two equivalent O(11), and two equivalent O(8) atoms. The Ba(1)-O(2) bond length is 2.74 Å. The Ba(1)-O(6) bond length is 2.75 Å. The Ba(1)-O(7) bond length is 2.71 Å. There is one shorter (3.01 Å) and one longer (3.16 Å) Ba(1)-O(1) bond length. There is one shorter (2.91 Å) and one longer (2.92 Å) Ba(1)-O(11) bond length. There is one shorter (2.73 Å) and one longer (2.98 Å) Ba(1)-O(8) bond length. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(2), one O(4), one O(6), one O(8), one O(9), two equivalent O(10), two equivalent O(3), and two equivalent O(5) atoms. The Ba(2)-O(2) bond length is 2.94 Å. The Ba(2)-O(4) bond length is 2.89 Å. The Ba(2)-O(6) bond length is 3.11 Å. The Ba(2)-O(8) bond length is 3.03 Å. The Ba(2)-O(9) bond length is 2.87 Å. There is one shorter (2.85 Å) and one longer (3.13 Å) Ba(2)-O(10) bond length. There is one shorter (2.80 Å) and one longer (3.26 Å) Ba(2)-O(3) bond length. There is one shorter (2.93 Å) and one longer (3.26 Å) Ba(2)-O(5) bond length. V(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form distorted VO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. The V(1)-O(1) bond length is 1.65 Å. The V(1)-O(2) bond length is 1.68 Å. The V(1)-O(3) bond length is 2.02 Å. The V(1)-O(4) bond length is 2.01 Å. The V(1)-O(5) bond length is 2.00 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one V(1)O5 trigonal bipyramid. The P(1)-O(3) bond length is 1.59 Å. The P(1)-O(6) bond length is 1.54 Å. The P(1)-O(7) bond length is 1.54 Å. The P(1)-O(8) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(10), one O(4), one O(5), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent V(1)O5 trigonal bipyramids. The P(2)-O(10) bond length is 1.52 Å. The P(2)-O(4) bond length is 1.56 Å. The P(2)-O(5) bond length is 1.59 Å. The P(2)-O(9) bond length is 1.56 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to two equivalent Ba(1) and one V(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one V(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Ba(2), one V(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one V(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent Ba(2), one V(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one P(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one Ba(2) and one P(2) atom. In the tenth O site, O(10) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one P(2) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to two equivalent Ba(1) atoms.