FeNbO4 crystallizes in the tetragonal P4_322 space group. Nb(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra and edges with two equivalent Nb(1)O6 octahedra. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-54°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Nb(1) and one Fe(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Nb(1) and one Fe(1) atom.
FeNbO4 crystallizes in the tetragonal P4_322 space group. Nb(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted NbO6 octahedra that share corners with six equivalent Fe(1)O4 tetrahedra and edges with two equivalent Nb(1)O6 octahedra. Both Nb(1)-O(1) bond lengths are 1.87 Å. There are two shorter (2.02 Å) and two longer (2.26 Å) Nb(1)-O(2) bond lengths. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form FeO4 tetrahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-54°. Both Fe(1)-O(1) bond lengths are 1.89 Å. Both Fe(1)-O(2) bond lengths are 1.93 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Nb(1) and one Fe(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Nb(1) and one Fe(1) atom.