Fe3Cu2Sb(PO4)6 crystallizes in the trigonal R3 space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(6) atoms. In the second Cu site, Cu(2) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(7) atoms. Sb(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form SbO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-49°. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-47°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Cu(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Fe(2), one Cu(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cu(1), one Sb(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Fe(3), one Cu(2), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom.
Fe3Cu2Sb(PO4)6 crystallizes in the trigonal R3 space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(2) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. All Fe(1)-O(2) bond lengths are 2.07 Å. All Fe(1)-O(5) bond lengths are 1.93 Å. In the second Fe site, Fe(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. All Fe(2)-O(1) bond lengths are 1.96 Å. All Fe(2)-O(4) bond lengths are 2.07 Å. In the third Fe site, Fe(3) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. All Fe(3)-O(7) bond lengths are 2.06 Å. All Fe(3)-O(8) bond lengths are 1.94 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(6) atoms. All Cu(1)-O(2) bond lengths are 2.15 Å. All Cu(1)-O(6) bond lengths are 2.35 Å. In the second Cu site, Cu(2) is bonded in a 6-coordinate geometry to three equivalent O(4) and three equivalent O(7) atoms. All Cu(2)-O(4) bond lengths are 2.22 Å. All Cu(2)-O(7) bond lengths are 2.22 Å. Sb(1) is bonded to three equivalent O(3) and three equivalent O(6) atoms to form SbO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. All Sb(1)-O(3) bond lengths are 1.96 Å. All Sb(1)-O(6) bond lengths are 2.01 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-49°. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.55 Å. The P(1)-O(8) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-47°. The P(2)-O(1) bond length is 1.52 Å. The P(2)-O(5) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.61 Å. The P(2)-O(7) bond length is 1.55 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one Cu(1), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sb(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Fe(2), one Cu(2), and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Cu(1), one Sb(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Fe(3), one Cu(2), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(3) and one P(1) atom.