SrFe3(PO4)3O crystallizes in the monoclinic P2_1/m space group. Sr(1) is bonded in a 7-coordinate geometry to one O(10), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(7), one O(8), and two equivalent O(3) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the third Fe site, Fe(3) is bonded to one O(10), one O(6), one O(8), one O(9), and two equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(7), one O(9), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. In the second P site, P(2) is bonded to one O(10), one O(8), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. In the third P site, P(3) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and  a cornercorner with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-56°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(2) and one P(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(3), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Sr(1), one Fe(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(2) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(3), and one P(2) atom.
SrFe3(PO4)3O crystallizes in the monoclinic P2_1/m space group. Sr(1) is bonded in a 7-coordinate geometry to one O(10), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. The Sr(1)-O(10) bond length is 2.64 Å. Both Sr(1)-O(3) bond lengths are 2.64 Å. Both Sr(1)-O(4) bond lengths are 2.60 Å. Both Sr(1)-O(5) bond lengths are 2.53 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(7), one O(8), and two equivalent O(3) atoms to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The Fe(1)-O(1) bond length is 1.94 Å. The Fe(1)-O(7) bond length is 1.90 Å. The Fe(1)-O(8) bond length is 2.02 Å. Both Fe(1)-O(3) bond lengths are 2.01 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 54°. Both Fe(2)-O(2) bond lengths are 2.15 Å. Both Fe(2)-O(5) bond lengths are 2.04 Å. Both Fe(2)-O(6) bond lengths are 2.02 Å. In the third Fe site, Fe(3) is bonded to one O(10), one O(6), one O(8), one O(9), and two equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. The Fe(3)-O(10) bond length is 2.13 Å. The Fe(3)-O(6) bond length is 1.93 Å. The Fe(3)-O(8) bond length is 2.30 Å. The Fe(3)-O(9) bond length is 1.97 Å. Both Fe(3)-O(4) bond lengths are 2.01 Å. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(7), one O(9), and two equivalent O(3) atoms to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O6 octahedra and corners with three equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. The P(1)-O(7) bond length is 1.55 Å. The P(1)-O(9) bond length is 1.52 Å. Both P(1)-O(3) bond lengths are 1.56 Å. In the second P site, P(2) is bonded to one O(10), one O(8), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. The P(2)-O(10) bond length is 1.55 Å. The P(2)-O(8) bond length is 1.57 Å. Both P(2)-O(5) bond lengths are 1.54 Å. In the third P site, P(3) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, and  a cornercorner with one Fe(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-56°. The P(3)-O(1) bond length is 1.53 Å. The P(3)-O(2) bond length is 1.58 Å. Both P(3)-O(4) bond lengths are 1.54 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Fe(2) and one P(3) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(3), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Sr(1), one Fe(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(2) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Sr(1), one Fe(3), and one P(2) atom.