Fe2CoO6 is Hydrophilite-derived structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-55°. In the second Fe site, Fe(2) is bonded to one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(4), two equivalent O(7), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(9) atoms to form CoO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Co(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Co(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(1) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom.
Fe2CoO6 is Hydrophilite-derived structured and crystallizes in the monoclinic C2 space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-55°. The Fe(1)-O(1) bond length is 2.01 Å. The Fe(1)-O(2) bond length is 1.99 Å. The Fe(1)-O(3) bond length is 2.00 Å. The Fe(1)-O(5) bond length is 2.03 Å. The Fe(1)-O(6) bond length is 2.06 Å. The Fe(1)-O(8) bond length is 1.99 Å. In the second Fe site, Fe(2) is bonded to one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. The Fe(2)-O(3) bond length is 1.86 Å. The Fe(2)-O(5) bond length is 1.91 Å. The Fe(2)-O(6) bond length is 1.90 Å. The Fe(2)-O(7) bond length is 1.88 Å. The Fe(2)-O(8) bond length is 1.88 Å. The Fe(2)-O(9) bond length is 1.89 Å. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. Both Fe(3)-O(1) bond lengths are 1.95 Å. Both Fe(3)-O(2) bond lengths are 1.94 Å. Both Fe(3)-O(4) bond lengths are 2.04 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(4), two equivalent O(7), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, and  an edgeedge with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-53°. Both Fe(4)-O(4) bond lengths are 1.96 Å. Both Fe(4)-O(7) bond lengths are 2.04 Å. Both Fe(4)-O(9) bond lengths are 2.01 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form CoO6 octahedra that share corners with two equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. The Co(1)-O(2) bond length is 1.86 Å. The Co(1)-O(3) bond length is 1.89 Å. The Co(1)-O(4) bond length is 1.83 Å. The Co(1)-O(5) bond length is 1.84 Å. The Co(1)-O(7) bond length is 1.87 Å. The Co(1)-O(8) bond length is 1.85 Å. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(9) atoms to form CoO6 octahedra that share corners with two equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. Both Co(2)-O(1) bond lengths are 1.84 Å. Both Co(2)-O(6) bond lengths are 1.88 Å. Both Co(2)-O(9) bond lengths are 1.86 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Co(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Co(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(1) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Co(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom.