Li3P7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 3-coordinate geometry to one P(5), two equivalent P(6), and two equivalent P(7) atoms. In the second Li site, Li(2) is bonded to one P(2), one P(3), one P(5), one P(6), and one P(7) atom to form distorted LiP5 tetrahedra that share corners with three equivalent P(1)LiP3 tetrahedra,  a cornercorner with one Li(3)P5 trigonal bipyramid, and  an edgeedge with one Li(3)P5 trigonal bipyramid. In the third Li site, Li(3) is bonded to one P(1), one P(2), one P(3), one P(4), and one P(5) atom to form distorted LiP5 trigonal bipyramids that share  a cornercorner with one Li(2)P5 tetrahedra,  a cornercorner with one P(1)LiP3 tetrahedra, corners with two equivalent P(5)Li3P2 trigonal bipyramids, and  an edgeedge with one Li(2)P5 tetrahedra. There are seven inequivalent P sites. In the first P site, P(6) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one P(1), and one P(3) atom. In the second P site, P(7) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one P(1), and one P(2) atom. In the third P site, P(1) is bonded to one Li(3), one P(5), one P(6), and one P(7) atom to form distorted PLiP3 tetrahedra that share corners with three equivalent Li(2)P5 tetrahedra,  a cornercorner with one Li(3)P5 trigonal bipyramid, and  a cornercorner with one P(5)Li3P2 trigonal bipyramid. In the fourth P site, P(2) is bonded in a 5-coordinate geometry to one Li(2), one Li(3), one P(3), one P(4), and one P(7) atom. In the fifth P site, P(3) is bonded in a 5-coordinate geometry to one Li(2), one Li(3), one P(2), one P(4), and one P(6) atom. In the sixth P site, P(4) is bonded in a 4-coordinate geometry to one Li(3), one P(2), one P(3), and one P(5) atom. In the seventh P site, P(5) is bonded to one Li(1), one Li(2), one Li(3), one P(1), and one P(4) atom to form distorted PLi3P2 trigonal bipyramids that share  a cornercorner with one P(1)LiP3 tetrahedra and corners with two equivalent Li(3)P5 trigonal bipyramids.
Li3P7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 3-coordinate geometry to one P(5), two equivalent P(6), and two equivalent P(7) atoms. The Li(1)-P(5) bond length is 2.70 Å. There is one shorter (2.62 Å) and one longer (2.96 Å) Li(1)-P(6) bond length. There is one shorter (2.63 Å) and one longer (2.98 Å) Li(1)-P(7) bond length. In the second Li site, Li(2) is bonded to one P(2), one P(3), one P(5), one P(6), and one P(7) atom to form distorted LiP5 tetrahedra that share corners with three equivalent P(1)LiP3 tetrahedra,  a cornercorner with one Li(3)P5 trigonal bipyramid, and  an edgeedge with one Li(3)P5 trigonal bipyramid. The Li(2)-P(2) bond length is 2.70 Å. The Li(2)-P(3) bond length is 3.10 Å. The Li(2)-P(5) bond length is 2.55 Å. The Li(2)-P(6) bond length is 2.55 Å. The Li(2)-P(7) bond length is 2.50 Å. In the third Li site, Li(3) is bonded to one P(1), one P(2), one P(3), one P(4), and one P(5) atom to form distorted LiP5 trigonal bipyramids that share  a cornercorner with one Li(2)P5 tetrahedra,  a cornercorner with one P(1)LiP3 tetrahedra, corners with two equivalent P(5)Li3P2 trigonal bipyramids, and  an edgeedge with one Li(2)P5 tetrahedra. The Li(3)-P(1) bond length is 2.61 Å. The Li(3)-P(2) bond length is 2.64 Å. The Li(3)-P(3) bond length is 2.91 Å. The Li(3)-P(4) bond length is 2.64 Å. The Li(3)-P(5) bond length is 2.61 Å. There are seven inequivalent P sites. In the first P site, P(6) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one P(1), and one P(3) atom. The P(6)-P(1) bond length is 2.18 Å. The P(6)-P(3) bond length is 2.13 Å. In the second P site, P(7) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one P(1), and one P(2) atom. The P(7)-P(1) bond length is 2.18 Å. The P(7)-P(2) bond length is 2.14 Å. In the third P site, P(1) is bonded to one Li(3), one P(5), one P(6), and one P(7) atom to form distorted PLiP3 tetrahedra that share corners with three equivalent Li(2)P5 tetrahedra,  a cornercorner with one Li(3)P5 trigonal bipyramid, and  a cornercorner with one P(5)Li3P2 trigonal bipyramid. The P(1)-P(5) bond length is 2.17 Å. In the fourth P site, P(2) is bonded in a 5-coordinate geometry to one Li(2), one Li(3), one P(3), one P(4), and one P(7) atom. The P(2)-P(3) bond length is 2.27 Å. The P(2)-P(4) bond length is 2.25 Å. In the fifth P site, P(3) is bonded in a 5-coordinate geometry to one Li(2), one Li(3), one P(2), one P(4), and one P(6) atom. The P(3)-P(4) bond length is 2.23 Å. In the sixth P site, P(4) is bonded in a 4-coordinate geometry to one Li(3), one P(2), one P(3), and one P(5) atom. The P(4)-P(5) bond length is 2.15 Å. In the seventh P site, P(5) is bonded to one Li(1), one Li(2), one Li(3), one P(1), and one P(4) atom to form distorted PLi3P2 trigonal bipyramids that share  a cornercorner with one P(1)LiP3 tetrahedra and corners with two equivalent Li(3)P5 trigonal bipyramids.