K3Tb(BO3)2 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(2) and four equivalent O(1) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Tb(1) is bonded in an octahedral geometry to two equivalent O(2) and four equivalent O(1) atoms. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(2), two equivalent K(1), one Tb(1), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Tb(1), and one B(1) atom.
K3Tb(BO3)2 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(2) and four equivalent O(1) atoms. Both K(1)-O(2) bond lengths are 2.82 Å. There are two shorter (2.78 Å) and two longer (2.79 Å) K(1)-O(1) bond lengths. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both K(2)-O(2) bond lengths are 2.81 Å. All K(2)-O(1) bond lengths are 2.75 Å. Tb(1) is bonded in an octahedral geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Tb(1)-O(2) bond lengths are 2.29 Å. All Tb(1)-O(1) bond lengths are 2.30 Å. B(1) is bonded in a trigonal planar geometry to one O(2) and two equivalent O(1) atoms. The B(1)-O(2) bond length is 1.39 Å. Both B(1)-O(1) bond lengths are 1.40 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(2), two equivalent K(1), one Tb(1), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Tb(1), and one B(1) atom.