FeTaO4 crystallizes in the monoclinic C2/m space group. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-30°. Fe(1) is bonded to one O(1), one O(2), one O(3), and three equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-35°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ta(1) and one Fe(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Ta(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ta(1) and one Fe(1) atom. In the fourth O site, O(4) is bonded to one Ta(1) and three equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OTaFe3 tetrahedra.
FeTaO4 crystallizes in the monoclinic C2/m space group. Ta(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-30°. The Ta(1)-O(2) bond length is 1.83 Å. The Ta(1)-O(4) bond length is 2.09 Å. There is one shorter (1.91 Å) and one longer (2.26 Å) Ta(1)-O(1) bond length. Both Ta(1)-O(3) bond lengths are 1.97 Å. Fe(1) is bonded to one O(1), one O(2), one O(3), and three equivalent O(4) atoms to form distorted FeO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-35°. The Fe(1)-O(1) bond length is 1.93 Å. The Fe(1)-O(2) bond length is 1.88 Å. The Fe(1)-O(3) bond length is 2.18 Å. There are two shorter (2.02 Å) and one longer (2.18 Å) Fe(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ta(1) and one Fe(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Ta(1) and one Fe(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ta(1) and one Fe(1) atom. In the fourth O site, O(4) is bonded to one Ta(1) and three equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OTaFe3 tetrahedra.