An original series of niobium cluster oxychloride compounds PbR3Nb6Cl15O6 has been obtained by solid-state chemistry. For R Lu and Gd the crystal structures determined by single-crystal X-ray diffraction technique. The compounds crystallize in a cubic system space group Pn-3 with four clusters per unit cell. Their structures are based on an octahedral cluster unit (Nb6Cli6Oi6)Cla6 in which the six chloride inner ligands are arranged in two sets of three on opposite sides of the Nb6 octahedron. Rare earth atoms form the R2Cl2 entities and link the clusters through oxide inner and chloride outer ligands. The Nb6Cl12O6 units interact with each other via both R2Cl2 entities and lead ions to form a three dimensional framework. Magnetic susceptibility studies on PbGd3Nb6Cl15O6 show paramagnetic behavior with an effective magnetic moment of 12.98 u8 per formula unit.