Li2VP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. V(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(5) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one V(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(2), one V(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(3), one V(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), two equivalent V(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Li(2), and one P(1) atom.
Li2VP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. The Li(1)-O(2) bond length is 1.99 Å. The Li(1)-O(5) bond length is 2.02 Å. The Li(1)-O(6) bond length is 1.88 Å. The Li(1)-O(7) bond length is 1.94 Å. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Both Li(2)-O(3) bond lengths are 2.01 Å. Both Li(2)-O(7) bond lengths are 1.89 Å. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Both Li(3)-O(4) bond lengths are 2.01 Å. Both Li(3)-O(6) bond lengths are 2.01 Å. V(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(5) atoms. The V(1)-O(2) bond length is 2.14 Å. The V(1)-O(3) bond length is 2.11 Å. The V(1)-O(4) bond length is 2.24 Å. There is one shorter (2.27 Å) and one longer (2.60 Å) V(1)-O(5) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. The P(1)-O(1) bond length is 1.65 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.54 Å. The P(1)-O(7) bond length is 1.51 Å. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, and  a cornercorner with one Li(3)O4 trigonal pyramid. The P(2)-O(1) bond length is 1.65 Å. The P(2)-O(3) bond length is 1.54 Å. The P(2)-O(5) bond length is 1.57 Å. The P(2)-O(6) bond length is 1.50 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one V(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(2), one V(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(3), one V(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Li(1), two equivalent V(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Li(2), and one P(1) atom.