Li3FeCO3PO4 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and one O(7) atom. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded in a tetrahedral geometry to one O(4), one O(5), one O(6), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Li(1), one Fe(1), and one C(1) atom. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), and one C(1) atom to form distorted OLi2FeC tetrahedra that share corners with two equivalent O(6)Li2FeP trigonal pyramids, corners with two equivalent O(5)Li3P trigonal pyramids, and  an edgeedge with one O(7)Li2FeP tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(3), one Fe(1), and one P(1) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Li(3), and one P(1) atom to form distorted OLi3P trigonal pyramids that share corners with two equivalent O(2)Li2FeC tetrahedra, corners with three equivalent O(7)Li2FeP tetrahedra,  a cornercorner with one O(6)Li2FeP trigonal pyramid, and  an edgeedge with one O(6)Li2FeP trigonal pyramid. In the sixth O site, O(6) is bonded to one Li(2), one Li(3), one Fe(1), and one P(1) atom to form distorted OLi2FeP trigonal pyramids that share corners with two equivalent O(2)Li2FeC tetrahedra, corners with four equivalent O(7)Li2FeP tetrahedra,  a cornercorner with one O(5)Li3P trigonal pyramid, and  an edgeedge with one O(5)Li3P trigonal pyramid. In the seventh O site, O(7) is bonded to one Li(2), one Li(3), one Fe(1), and one P(1) atom to form OLi2FeP tetrahedra that share corners with three equivalent O(5)Li3P trigonal pyramids, corners with four equivalent O(6)Li2FeP trigonal pyramids, and  an edgeedge with one O(2)Li2FeC tetrahedra.
Li3FeCO3PO4 crystallizes in the monoclinic P2_1 space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(4), and one O(5) atom. The Li(1)-O(1) bond length is 1.90 Å. The Li(1)-O(2) bond length is 2.00 Å. The Li(1)-O(4) bond length is 2.27 Å. The Li(1)-O(5) bond length is 2.08 Å. In the second Li site, Li(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and one O(7) atom. The Li(2)-O(2) bond length is 2.30 Å. The Li(2)-O(3) bond length is 2.53 Å. The Li(2)-O(5) bond length is 2.05 Å. The Li(2)-O(6) bond length is 2.06 Å. The Li(2)-O(7) bond length is 2.10 Å. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Li(3)-O(3) bond length is 2.24 Å. The Li(3)-O(4) bond length is 2.11 Å. The Li(3)-O(5) bond length is 2.00 Å. The Li(3)-O(6) bond length is 2.09 Å. The Li(3)-O(7) bond length is 2.06 Å. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. The Fe(1)-O(1) bond length is 2.66 Å. The Fe(1)-O(2) bond length is 2.19 Å. The Fe(1)-O(3) bond length is 2.07 Å. The Fe(1)-O(4) bond length is 2.07 Å. The Fe(1)-O(6) bond length is 2.15 Å. The Fe(1)-O(7) bond length is 2.22 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(2) bond length is 1.32 Å. The C(1)-O(3) bond length is 1.30 Å. P(1) is bonded in a tetrahedral geometry to one O(4), one O(5), one O(6), and one O(7) atom. The P(1)-O(4) bond length is 1.56 Å. The P(1)-O(5) bond length is 1.55 Å. The P(1)-O(6) bond length is 1.55 Å. The P(1)-O(7) bond length is 1.57 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Li(1), one Fe(1), and one C(1) atom. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), and one C(1) atom to form distorted OLi2FeC tetrahedra that share corners with two equivalent O(6)Li2FeP trigonal pyramids, corners with two equivalent O(5)Li3P trigonal pyramids, and  an edgeedge with one O(7)Li2FeP tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Li(2), one Li(3), one Fe(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(3), one Fe(1), and one P(1) atom. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Li(3), and one P(1) atom to form distorted OLi3P trigonal pyramids that share corners with two equivalent O(2)Li2FeC tetrahedra, corners with three equivalent O(7)Li2FeP tetrahedra,  a cornercorner with one O(6)Li2FeP trigonal pyramid, and  an edgeedge with one O(6)Li2FeP trigonal pyramid. In the sixth O site, O(6) is bonded to one Li(2), one Li(3), one Fe(1), and one P(1) atom to form distorted OLi2FeP trigonal pyramids that share corners with two equivalent O(2)Li2FeC tetrahedra, corners with four equivalent O(7)Li2FeP tetrahedra,  a cornercorner with one O(5)Li3P trigonal pyramid, and  an edgeedge with one O(5)Li3P trigonal pyramid. In the seventh O site, O(7) is bonded to one Li(2), one Li(3), one Fe(1), and one P(1) atom to form OLi2FeP tetrahedra that share corners with three equivalent O(5)Li3P trigonal pyramids, corners with four equivalent O(6)Li2FeP trigonal pyramids, and  an edgeedge with one O(2)Li2FeC tetrahedra.