FePbP2O7 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. Pb(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(6), one O(7), and two equivalent O(1) atoms. 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(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Pb(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Pb(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Fe(1), one Pb(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Fe(1), one Pb(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Fe(1), one Pb(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Pb(1), and one P(2) atom.
FePbP2O7 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Fe(1)-O(2) bond length is 2.08 Å. The Fe(1)-O(3) bond length is 2.20 Å. The Fe(1)-O(4) bond length is 2.05 Å. The Fe(1)-O(6) bond length is 2.13 Å. The Fe(1)-O(7) bond length is 2.13 Å. Pb(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(6), one O(7), and two equivalent O(1) atoms. The Pb(1)-O(2) bond length is 2.77 Å. The Pb(1)-O(3) bond length is 2.57 Å. The Pb(1)-O(4) bond length is 2.73 Å. The Pb(1)-O(6) bond length is 2.76 Å. The Pb(1)-O(7) bond length is 2.75 Å. There is one shorter (2.48 Å) and one longer (2.71 Å) Pb(1)-O(1) bond length. 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(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.53 Å. The P(1)-O(5) bond length is 1.62 Å. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. The P(2)-O(2) bond length is 1.55 Å. The P(2)-O(5) bond length is 1.63 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.54 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Pb(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Pb(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Fe(1), one Pb(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Fe(1), one Pb(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Fe(1), one Pb(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Pb(1), and one P(2) atom.