KTb(FeO3)4 crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(4) atoms to form distorted KO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra and faces with eight equivalent Fe(1)O6 octahedra. Tb(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and four equivalent O(1) atoms. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra and faces with two equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-21°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted square co-planar geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted square co-planar geometry to two equivalent K(1) and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Tb(1) and two equivalent Fe(1) atoms.
KTb(FeO3)4 crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(4) atoms to form distorted KO12 cuboctahedra that share corners with four equivalent K(1)O12 cuboctahedra and faces with eight equivalent Fe(1)O6 octahedra. Both K(1)-O(2) bond lengths are 3.06 Å. Both K(1)-O(3) bond lengths are 2.80 Å. All K(1)-O(1) bond lengths are 2.85 Å. There are two shorter (2.69 Å) and two longer (2.74 Å) K(1)-O(4) bond lengths. Tb(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(5), and four equivalent O(1) atoms. Both Tb(1)-O(2) bond lengths are 2.47 Å. Both Tb(1)-O(3) bond lengths are 2.52 Å. Both Tb(1)-O(5) bond lengths are 2.42 Å. All Tb(1)-O(1) bond lengths are 2.55 Å. Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form FeO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra and faces with two equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 5-21°. The Fe(1)-O(2) bond length is 1.93 Å. The Fe(1)-O(3) bond length is 1.93 Å. The Fe(1)-O(4) bond length is 1.89 Å. The Fe(1)-O(5) bond length is 1.94 Å. There is one shorter (1.92 Å) and one longer (1.94 Å) Fe(1)-O(1) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted square co-planar geometry to one K(1), one Tb(1), and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted square co-planar geometry to two equivalent K(1) and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Tb(1) and two equivalent Fe(1) atoms.