FeTa2O6 is Hydrophilite-derived structured and crystallizes in the monoclinic P2 space group. There are eight inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(13), two equivalent O(6), and two equivalent O(9) atoms to form TaO6 octahedra that share corners with four equivalent Ta(3)O6 octahedra, corners with four equivalent Ta(5)O6 octahedra,  an edgeedge with one Ta(8)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-52°. In the second Ta site, Ta(2) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(5) atom to form TaO6 octahedra that share corners with two equivalent Ta(5)O6 octahedra, corners with two equivalent Ta(6)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ta(7)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-53°. In the third Ta site, Ta(3) is bonded to one O(13), one O(14), one O(16), one O(18), one O(7), and one O(9) atom to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, corners with two equivalent Ta(8)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. In the fourth Ta site, Ta(4) is bonded to two equivalent O(15), two equivalent O(17), and two equivalent O(8) atoms to form TaO6 octahedra that share corners with four equivalent Ta(7)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(6)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. In the fifth Ta site, Ta(5) is bonded to one O(10), one O(12), one O(13), one O(16), one O(4), and one O(6) atom to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. In the sixth Ta site, Ta(6) is bonded to two equivalent O(11), two equivalent O(15), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with four equivalent Ta(2)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. In the seventh Ta site, Ta(7) is bonded to one O(1), one O(17), one O(18), one O(2), one O(7), and one O(8) atom to form TaO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. In the eighth Ta site, Ta(8) is bonded to two equivalent O(14), two equivalent O(3), and two equivalent O(9) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ta(3)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-62°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(10), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with four equivalent Ta(5)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-59°. In the second Fe site, Fe(2) is bonded to one O(15), one O(16), one O(4), one O(5), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with two equivalent Ta(5)O6 octahedra, corners with two equivalent Ta(6)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(12), one O(14), one O(18), and one O(3) atom to form FeO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, corners with two equivalent Ta(8)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-62°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(11), two equivalent O(17), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with four equivalent Ta(2)O6 octahedra, corners with four equivalent Ta(7)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ta(2), one Ta(7), and one Fe(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ta(2), one Ta(7), and one Fe(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ta(8), one Fe(1), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(5), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(6), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(5), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(7), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ta(4), one Ta(7), and one Fe(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(8) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ta(5), one Fe(1), and one Fe(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(6), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ta(2), one Ta(5), and one Fe(3) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(8), and one Fe(3) atom. In the fifteenth O site, O(15) is bonded in a trigonal planar geometry to one Ta(4), one Ta(6), and one Fe(2) atom. In the sixteenth O site, O(16) is bonded in a trigonal planar geometry to one Ta(3), one Ta(5), and one Fe(2) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Ta(4), one Ta(7), and one Fe(4) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Ta(3), one Ta(7), and one Fe(3) atom.
FeTa2O6 is Hydrophilite-derived structured and crystallizes in the monoclinic P2 space group. There are eight inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(13), two equivalent O(6), and two equivalent O(9) atoms to form TaO6 octahedra that share corners with four equivalent Ta(3)O6 octahedra, corners with four equivalent Ta(5)O6 octahedra,  an edgeedge with one Ta(8)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-52°. Both Ta(1)-O(13) bond lengths are 2.05 Å. Both Ta(1)-O(6) bond lengths are 1.94 Å. Both Ta(1)-O(9) bond lengths are 2.03 Å. In the second Ta site, Ta(2) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(5) atom to form TaO6 octahedra that share corners with two equivalent Ta(5)O6 octahedra, corners with two equivalent Ta(6)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ta(7)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-53°. The Ta(2)-O(1) bond length is 2.03 Å. The Ta(2)-O(11) bond length is 1.99 Å. The Ta(2)-O(12) bond length is 2.01 Å. The Ta(2)-O(2) bond length is 2.04 Å. The Ta(2)-O(4) bond length is 1.97 Å. The Ta(2)-O(5) bond length is 1.99 Å. In the third Ta site, Ta(3) is bonded to one O(13), one O(14), one O(16), one O(18), one O(7), and one O(9) atom to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, corners with two equivalent Ta(8)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(5)O6 octahedra, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-56°. The Ta(3)-O(13) bond length is 2.11 Å. The Ta(3)-O(14) bond length is 1.97 Å. The Ta(3)-O(16) bond length is 1.97 Å. The Ta(3)-O(18) bond length is 1.94 Å. The Ta(3)-O(7) bond length is 2.00 Å. The Ta(3)-O(9) bond length is 2.07 Å. In the fourth Ta site, Ta(4) is bonded to two equivalent O(15), two equivalent O(17), and two equivalent O(8) atoms to form TaO6 octahedra that share corners with four equivalent Ta(7)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(6)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. Both Ta(4)-O(15) bond lengths are 2.02 Å. Both Ta(4)-O(17) bond lengths are 2.00 Å. Both Ta(4)-O(8) bond lengths are 2.00 Å. In the fifth Ta site, Ta(5) is bonded to one O(10), one O(12), one O(13), one O(16), one O(4), and one O(6) atom to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-59°. The Ta(5)-O(10) bond length is 1.87 Å. The Ta(5)-O(12) bond length is 1.95 Å. The Ta(5)-O(13) bond length is 2.12 Å. The Ta(5)-O(16) bond length is 2.12 Å. The Ta(5)-O(4) bond length is 2.01 Å. The Ta(5)-O(6) bond length is 2.02 Å. In the sixth Ta site, Ta(6) is bonded to two equivalent O(11), two equivalent O(15), and two equivalent O(5) atoms to form TaO6 octahedra that share corners with four equivalent Ta(2)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. Both Ta(6)-O(11) bond lengths are 1.99 Å. Both Ta(6)-O(15) bond lengths are 2.03 Å. Both Ta(6)-O(5) bond lengths are 2.00 Å. In the seventh Ta site, Ta(7) is bonded to one O(1), one O(17), one O(18), one O(2), one O(7), and one O(8) atom to form TaO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. The Ta(7)-O(1) bond length is 2.03 Å. The Ta(7)-O(17) bond length is 1.98 Å. The Ta(7)-O(18) bond length is 2.03 Å. The Ta(7)-O(2) bond length is 2.02 Å. The Ta(7)-O(7) bond length is 1.99 Å. The Ta(7)-O(8) bond length is 1.99 Å. In the eighth Ta site, Ta(8) is bonded to two equivalent O(14), two equivalent O(3), and two equivalent O(9) atoms to form distorted TaO6 octahedra that share corners with four equivalent Ta(3)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-62°. Both Ta(8)-O(14) bond lengths are 2.01 Å. Both Ta(8)-O(3) bond lengths are 1.86 Å. Both Ta(8)-O(9) bond lengths are 2.22 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(10), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with four equivalent Ta(5)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-59°. Both Fe(1)-O(10) bond lengths are 2.04 Å. Both Fe(1)-O(3) bond lengths are 2.19 Å. Both Fe(1)-O(6) bond lengths are 2.24 Å. In the second Fe site, Fe(2) is bonded to one O(15), one O(16), one O(4), one O(5), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Ta(3)O6 octahedra, corners with two equivalent Ta(4)O6 octahedra, corners with two equivalent Ta(5)O6 octahedra, corners with two equivalent Ta(6)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. The Fe(2)-O(15) bond length is 2.17 Å. The Fe(2)-O(16) bond length is 2.12 Å. The Fe(2)-O(4) bond length is 2.18 Å. The Fe(2)-O(5) bond length is 2.21 Å. The Fe(2)-O(7) bond length is 2.19 Å. The Fe(2)-O(8) bond length is 2.20 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(10), one O(12), one O(14), one O(18), and one O(3) atom to form FeO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with two equivalent Ta(7)O6 octahedra, corners with two equivalent Ta(8)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-62°. The Fe(3)-O(1) bond length is 2.12 Å. The Fe(3)-O(10) bond length is 2.18 Å. The Fe(3)-O(12) bond length is 2.24 Å. The Fe(3)-O(14) bond length is 2.23 Å. The Fe(3)-O(18) bond length is 2.22 Å. The Fe(3)-O(3) bond length is 2.03 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(11), two equivalent O(17), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with four equivalent Ta(2)O6 octahedra, corners with four equivalent Ta(7)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. Both Fe(4)-O(11) bond lengths are 2.19 Å. Both Fe(4)-O(17) bond lengths are 2.19 Å. Both Fe(4)-O(2) bond lengths are 2.14 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ta(2), one Ta(7), and one Fe(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ta(2), one Ta(7), and one Fe(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ta(8), one Fe(1), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(5), and one Fe(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(6), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(5), and one Fe(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(7), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Ta(4), one Ta(7), and one Fe(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(8) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ta(5), one Fe(1), and one Fe(3) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ta(2), one Ta(6), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ta(2), one Ta(5), and one Fe(3) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(8), and one Fe(3) atom. In the fifteenth O site, O(15) is bonded in a trigonal planar geometry to one Ta(4), one Ta(6), and one Fe(2) atom. In the sixteenth O site, O(16) is bonded in a trigonal planar geometry to one Ta(3), one Ta(5), and one Fe(2) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Ta(4), one Ta(7), and one Fe(4) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Ta(3), one Ta(7), and one Fe(3) atom.