FeZnP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(7), and two equivalent O(6) atoms to form FeO5 square pyramids that share corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; corners with two Zn(1,1)O5 trigonal bipyramids; and  an edgeedge with one Fe(1)O5 square pyramid. In the second Fe site, Fe(1) is bonded to one O(2), one O(4), one O(7), and two equivalent O(6) atoms to form FeO5 square pyramids that share corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; corners with two Zn(1,1)O5 trigonal bipyramids; and  an edgeedge with one Fe(1)O5 square pyramid. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form ZnO5 trigonal bipyramids that share corners with two Fe(1,1)O5 square pyramids; corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; and  an edgeedge with one Zn(1)O5 trigonal bipyramid. In the second Zn site, Zn(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form ZnO5 trigonal bipyramids that share corners with two Fe(1,1)O5 square pyramids; corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; and  an edgeedge with one Zn(1)O5 trigonal bipyramid. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three Fe(1,1)O5 square pyramids;  a cornercorner with one P(2)O4 tetrahedra; and corners with three Zn(1,1)O5 trigonal bipyramids. In the second P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three Fe(1,1)O5 square pyramids;  a cornercorner with one P(2)O4 tetrahedra; and corners with three Zn(1,1)O5 trigonal bipyramids. In the third P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two Fe(1,1)O5 square pyramids;  a cornercorner with one P(1)O4 tetrahedra; and corners with two Zn(1,1)O5 trigonal bipyramids. In the fourth P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two Fe(1,1)O5 square pyramids;  a cornercorner with one P(1)O4 tetrahedra; and corners with two Zn(1,1)O5 trigonal bipyramids. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one P(2) atom. In the sixth O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(2) atom. In the eighth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(2) atom. In the ninth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom. In the tenth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom. In the eleventh O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the twelfth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the thirteenth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the fourteenth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom.
FeZnP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(4), one O(7), and two equivalent O(6) atoms to form FeO5 square pyramids that share corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; corners with two Zn(1,1)O5 trigonal bipyramids; and  an edgeedge with one Fe(1)O5 square pyramid. The Fe(1)-O(2) bond length is 2.30 Å. The Fe(1)-O(4) bond length is 2.05 Å. The Fe(1)-O(7) bond length is 1.97 Å. There is one shorter (2.15 Å) and one longer (2.17 Å) Fe(1)-O(6) bond length. In the second Fe site, Fe(1) is bonded to one O(2), one O(4), one O(7), and two equivalent O(6) atoms to form FeO5 square pyramids that share corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; corners with two Zn(1,1)O5 trigonal bipyramids; and  an edgeedge with one Fe(1)O5 square pyramid. The Fe(1)-O(2) bond length is 2.31 Å. The Fe(1)-O(4) bond length is 2.05 Å. The Fe(1)-O(7) bond length is 1.97 Å. There is one shorter (2.16 Å) and one longer (2.17 Å) Fe(1)-O(6) bond length. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form ZnO5 trigonal bipyramids that share corners with two Fe(1,1)O5 square pyramids; corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; and  an edgeedge with one Zn(1)O5 trigonal bipyramid. The Zn(1)-O(2) bond length is 2.14 Å. The Zn(1)-O(3) bond length is 1.97 Å. The Zn(1)-O(4) bond length is 2.18 Å. There is one shorter (2.08 Å) and one longer (2.10 Å) Zn(1)-O(5) bond length. In the second Zn site, Zn(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form ZnO5 trigonal bipyramids that share corners with two Fe(1,1)O5 square pyramids; corners with two P(2,2)O4 tetrahedra; corners with three P(1,1)O4 tetrahedra; and  an edgeedge with one Zn(1)O5 trigonal bipyramid. The Zn(1)-O(2) bond length is 2.15 Å. The Zn(1)-O(3) bond length is 1.97 Å. The Zn(1)-O(4) bond length is 2.18 Å. There is one shorter (2.07 Å) and one longer (2.10 Å) Zn(1)-O(5) bond length. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three Fe(1,1)O5 square pyramids;  a cornercorner with one P(2)O4 tetrahedra; and corners with three Zn(1,1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.60 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.54 Å. The P(1)-O(6) bond length is 1.53 Å. In the second P site, P(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three Fe(1,1)O5 square pyramids;  a cornercorner with one P(2)O4 tetrahedra; and corners with three Zn(1,1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.60 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.54 Å. The P(1)-O(6) bond length is 1.53 Å. In the third P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two Fe(1,1)O5 square pyramids;  a cornercorner with one P(1)O4 tetrahedra; and corners with two Zn(1,1)O5 trigonal bipyramids. The P(2)-O(1) bond length is 1.63 Å. The P(2)-O(3) bond length is 1.52 Å. The P(2)-O(4) bond length is 1.56 Å. The P(2)-O(7) bond length is 1.51 Å. In the fourth P site, P(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form PO4 tetrahedra that share corners with two Fe(1,1)O5 square pyramids;  a cornercorner with one P(1)O4 tetrahedra; and corners with two Zn(1,1)O5 trigonal bipyramids. The P(2)-O(1) bond length is 1.63 Å. The P(2)-O(3) bond length is 1.52 Å. The P(2)-O(4) bond length is 1.56 Å. The P(2)-O(7) bond length is 1.51 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(1) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one P(2) atom. In the sixth O site, O(3) is bonded in a bent 120 degrees geometry to one Zn(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(2) atom. In the eighth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one P(2) atom. In the ninth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom. In the tenth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom. In the eleventh O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the twelfth O site, O(6) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the thirteenth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom. In the fourteenth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(2) atom.