Li4P2O7 is Clathrate-derived structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(4)O4 tetrahedra. In the second Li site, Li(2) 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(3)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(1), one O(6), and two equivalent O(7) atoms to form LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. In the fourth Li site, Li(4) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(4)O4 tetrahedra. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and  an edgeedge with one Li(4)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded to one Li(1), one Li(2), one Li(3), and one P(2) atom to form a mixture of corner and edge-sharing OLi3P tetrahedra. In the second O site, O(7) is bonded to one Li(2), two equivalent Li(3), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi3P trigonal pyramids. In the third O site, O(1) is bonded in a trigonal planar geometry to one Li(3), one Li(4), and one P(1) atom. In the fourth O site, O(2) is bonded to one Li(1), one Li(2), one Li(4), and one P(2) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the fifth O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Li(4), and one P(1) atom. In the sixth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(4), one P(1), and one P(2) atom. In the seventh O site, O(5) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom.
Li4P2O7 is Clathrate-derived structured and crystallizes in the monoclinic P2_1/c space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form LiO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(4)O4 tetrahedra. The Li(1)-O(2) bond length is 2.04 Å. The Li(1)-O(3) bond length is 1.97 Å. The Li(1)-O(5) bond length is 1.96 Å. The Li(1)-O(6) bond length is 2.05 Å. In the second Li site, Li(2) 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(3)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The Li(2)-O(2) bond length is 1.97 Å. The Li(2)-O(5) bond length is 1.95 Å. The Li(2)-O(6) bond length is 2.02 Å. The Li(2)-O(7) bond length is 2.03 Å. In the third Li site, Li(3) is bonded to one O(1), one O(6), and two equivalent O(7) atoms to form LiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(4)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Li(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The Li(3)-O(1) bond length is 1.91 Å. The Li(3)-O(6) bond length is 1.99 Å. There is one shorter (1.97 Å) and one longer (2.01 Å) Li(3)-O(7) bond length. In the fourth Li site, Li(4) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one Li(3)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  an edgeedge with one Li(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The Li(4)-O(1) bond length is 1.90 Å. The Li(4)-O(2) bond length is 2.07 Å. The Li(4)-O(3) bond length is 1.91 Å. The Li(4)-O(4) bond length is 2.09 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent Li(3)O4 tetrahedra, and corners with three equivalent Li(4)O4 tetrahedra. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(4) bond length is 1.65 Å. The P(1)-O(7) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Li(3)O4 tetrahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Li(2)O4 tetrahedra, and  an edgeedge with one Li(4)O4 tetrahedra. The P(2)-O(2) bond length is 1.54 Å. The P(2)-O(4) bond length is 1.65 Å. The P(2)-O(5) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.54 Å. There are seven inequivalent O sites. In the first O site, O(6) is bonded to one Li(1), one Li(2), one Li(3), and one P(2) atom to form a mixture of corner and edge-sharing OLi3P tetrahedra. In the second O site, O(7) is bonded to one Li(2), two equivalent Li(3), and one P(1) atom to form a mixture of distorted corner and edge-sharing OLi3P trigonal pyramids. In the third O site, O(1) is bonded in a trigonal planar geometry to one Li(3), one Li(4), and one P(1) atom. In the fourth O site, O(2) is bonded to one Li(1), one Li(2), one Li(4), and one P(2) atom to form distorted corner-sharing OLi3P trigonal pyramids. In the fifth O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one Li(4), and one P(1) atom. In the sixth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(4), one P(1), and one P(2) atom. In the seventh O site, O(5) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one P(2) atom.