FeZnAsO5 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(2), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted T-shaped geometry to one O(4), one O(5), and one O(9) atom. In the second Zn site, Zn(2) is bonded in a distorted T-shaped geometry to one O(10), one O(3), and one O(6) atom. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-58°. In the second As site, As(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-58°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one As(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one As(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Zn(2), and one As(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(2) and one As(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(2) atom. In the ninth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Zn(1) atom. In the tenth O site, O(10) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Zn(2) atom.
FeZnAsO5 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. The Fe(1)-O(1) bond length is 2.15 Å. The Fe(1)-O(10) bond length is 1.97 Å. The Fe(1)-O(2) bond length is 2.08 Å. The Fe(1)-O(5) bond length is 2.12 Å. The Fe(1)-O(8) bond length is 2.06 Å. The Fe(1)-O(9) bond length is 1.98 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(2), one O(6), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. The Fe(2)-O(1) bond length is 2.12 Å. The Fe(2)-O(10) bond length is 1.99 Å. The Fe(2)-O(2) bond length is 2.12 Å. The Fe(2)-O(6) bond length is 2.12 Å. The Fe(2)-O(7) bond length is 2.07 Å. The Fe(2)-O(9) bond length is 1.92 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted T-shaped geometry to one O(4), one O(5), and one O(9) atom. The Zn(1)-O(4) bond length is 1.88 Å. The Zn(1)-O(5) bond length is 2.15 Å. The Zn(1)-O(9) bond length is 1.88 Å. In the second Zn site, Zn(2) is bonded in a distorted T-shaped geometry to one O(10), one O(3), and one O(6) atom. The Zn(2)-O(10) bond length is 1.88 Å. The Zn(2)-O(3) bond length is 1.87 Å. The Zn(2)-O(6) bond length is 2.09 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-58°. The As(1)-O(1) bond length is 1.74 Å. The As(1)-O(3) bond length is 1.72 Å. The As(1)-O(5) bond length is 1.73 Å. The As(1)-O(7) bond length is 1.73 Å. In the second As site, As(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-58°. The As(2)-O(2) bond length is 1.75 Å. The As(2)-O(4) bond length is 1.71 Å. The As(2)-O(6) bond length is 1.73 Å. The As(2)-O(8) bond length is 1.72 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one As(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one As(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Zn(2), and one As(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(2) and one As(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(2) atom. In the ninth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Zn(1) atom. In the tenth O site, O(10) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Zn(2) atom.