Li4MoP2O9 crystallizes in the monoclinic C2/m space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(7), and two equivalent O(4) atoms. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(5), one O(7), and two equivalent O(6) atoms. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to two equivalent O(2) and two equivalent O(4) atoms. Mo(1) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one Li(2), two equivalent Li(3), and one P(1) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Mo(1), and one P(2) atom. In the third O site, O(7) is bonded to one Li(1), one Li(2), and two equivalent Mo(1) atoms to form corner-sharing OLi2Mo2 tetrahedra. In the fourth O site, O(1) is bonded in a distorted linear geometry to one Li(2) and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Li(4), and one P(2) atom. In the sixth O site, O(3) is bonded in a distorted linear geometry to one Li(1), two equivalent Li(3), and one P(2) atom. In the seventh O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(4), one Mo(1), and one P(1) atom.
Li4MoP2O9 crystallizes in the monoclinic C2/m space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(7), and two equivalent O(4) atoms. The Li(1)-O(2) bond length is 1.98 Å. The Li(1)-O(3) bond length is 1.81 Å. The Li(1)-O(7) bond length is 2.18 Å. Both Li(1)-O(4) bond lengths are 2.43 Å. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(1), one O(5), one O(7), and two equivalent O(6) atoms. The Li(2)-O(1) bond length is 1.85 Å. The Li(2)-O(5) bond length is 1.94 Å. The Li(2)-O(7) bond length is 2.26 Å. Both Li(2)-O(6) bond lengths are 2.37 Å. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. Both Li(3)-O(3) bond lengths are 2.60 Å. Both Li(3)-O(5) bond lengths are 2.31 Å. Both Li(3)-O(6) bond lengths are 2.12 Å. In the fourth Li site, Li(4) is bonded in a 4-coordinate geometry to two equivalent O(2) and two equivalent O(4) atoms. Both Li(4)-O(2) bond lengths are 2.14 Å. Both Li(4)-O(4) bond lengths are 2.08 Å. Mo(1) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. Both Mo(1)-O(4) bond lengths are 2.07 Å. Both Mo(1)-O(6) bond lengths are 2.10 Å. Both Mo(1)-O(7) bond lengths are 2.00 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(5), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. The P(1)-O(1) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.53 Å. Both P(1)-O(4) bond lengths are 1.60 Å. In the second P site, P(2) is bonded to one O(2), one O(3), and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. The P(2)-O(2) bond length is 1.54 Å. The P(2)-O(3) bond length is 1.51 Å. Both P(2)-O(6) bond lengths are 1.59 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one Li(2), two equivalent Li(3), and one P(1) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Mo(1), and one P(2) atom. In the third O site, O(7) is bonded to one Li(1), one Li(2), and two equivalent Mo(1) atoms to form corner-sharing OLi2Mo2 tetrahedra. In the fourth O site, O(1) is bonded in a distorted linear geometry to one Li(2) and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Li(4), and one P(2) atom. In the sixth O site, O(3) is bonded in a distorted linear geometry to one Li(1), two equivalent Li(3), and one P(2) atom. In the seventh O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Li(4), one Mo(1), and one P(1) atom.