Li4P2O7 is Clathrate-derived structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form LiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(3)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 one O(2), one O(3), one O(4), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(7) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, and corners with two equivalent Li(3)O4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the second O site, O(2) is bonded to one Li(2), one Li(3), one Li(4), and one P(2) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the third O site, O(3) is bonded to one Li(3), two equivalent Li(1), and one P(2) atom to form a mixture of distorted corner and edge-sharing OLi3P trigonal pyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(3), one Li(4), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Li(2), one Li(4), and one P(1) atom. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Li(3), and one P(1) atom to form a mixture of corner and edge-sharing OLi3P tetrahedra. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Li(4), one P(1), and one P(2) atom.
Li4P2O7 is Clathrate-derived structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form LiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The Li(1)-O(1) bond length is 1.87 Å. The Li(1)-O(6) bond length is 1.93 Å. There is one shorter (1.95 Å) and one longer (1.96 Å) Li(1)-O(3) bond length. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The Li(2)-O(1) bond length is 1.91 Å. The Li(2)-O(2) bond length is 1.99 Å. The Li(2)-O(5) bond length is 1.92 Å. The Li(2)-O(6) bond length is 1.99 Å. In the third Li site, Li(3) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The Li(3)-O(2) bond length is 1.92 Å. The Li(3)-O(3) bond length is 1.99 Å. The Li(3)-O(4) bond length is 1.91 Å. The Li(3)-O(6) bond length is 1.98 Å. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and one O(7) atom. The Li(4)-O(2) bond length is 2.07 Å. The Li(4)-O(4) bond length is 1.86 Å. The Li(4)-O(5) bond length is 1.87 Å. The Li(4)-O(7) bond length is 2.04 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, and corners with two equivalent Li(3)O4 tetrahedra. The P(1)-O(4) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.50 Å. The P(1)-O(6) bond length is 1.53 Å. The P(1)-O(7) bond length is 1.63 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(1)O4 tetrahedra. The P(2)-O(1) bond length is 1.50 Å. The P(2)-O(2) bond length is 1.52 Å. The P(2)-O(3) bond length is 1.52 Å. The P(2)-O(7) bond length is 1.63 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom. In the second O site, O(2) is bonded to one Li(2), one Li(3), one Li(4), and one P(2) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the third O site, O(3) is bonded to one Li(3), two equivalent Li(1), and one P(2) atom to form a mixture of distorted corner and edge-sharing OLi3P trigonal pyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(3), one Li(4), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Li(2), one Li(4), and one P(1) atom. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Li(3), and one P(1) atom to form a mixture of corner and edge-sharing OLi3P tetrahedra. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Li(4), one P(1), and one P(2) atom.