The reactions of Ln(2)O(3)/CeO2/Pr6O11 (Ln = La-Nd, Sm), molten boric acid, and concentrated HBr or HI result in the formation of La[B7O10(OH)(3)(H2O)Br], Ln[B6O9(OH)(2)(H2O)(2)Br]center dot 0.5H(2)O (Ln = Ce, Pr), Nd-2[B12O17.5(OH)(5)(H2O)(4)Br-1.5]Br-0.5 center dot H2O (NdBOBr), Sm-4[B18O25(OH)(13)Br-3], and Ln[B7O11(OH)(H2O)(3)I] (Ln = La-Nd, Sm). The lanthanide(III) centers in these compounds are found with 9-coordinate hula hoop or 10-coordinate capped triangular cupola geometries, where there are six approximately coplanar oxygen donors provided by the polyborate sheet. The sheets are formed into three-dimensional frameworks via BO3 triangles that are roughly perpendicular to the layers. Additionally, a new cationic framework, NdBOBr, has been isolated. NdBOBr is unusual in that not only is it a cationic framework, but it is also the first trivalent f-element borate to have terminal halides bound exclusively to the base site of the hula hoop. The Ln[B7O11(OH)(H2O)(3)I] (Ln = La-Nd, Sm) structures require two corner-shared BO3 units in order to tether the layers together because of the large size of the capping iodine atom.