The first Lanthanide heteropolyvanadates with transition metal central atoms were synthesized by ion exchange and double decomposition reaction. General formula of the complexes is Ln2H[MV13O38].nH2O(Ln=La, Ce, Pr, Nd, Sm, Eu; M=Ni, Mn). The structure has been characterized by IR, ^5^1V NMR, ESR, magnetic susceptibility and elemental analysis. The MTT experiments show that praseodymium salts of 13-vanadomangamate(IV) and nickelate(IV) heteropoly anions have stronger killing ability for many kinds of cancer cells and stronger antitumour activity in vitro.

Key words: INFRARED SPECTROPHOTOMETRY, HETEROPOLYACID, LANTHANUM COMPOUNDS, ELEMENTAL ANALYSIS, PARAMAGNETIC RESONANCE, NEODYMIUM COMPOUNDS, EUROPIUM COMPOUNDS, CERIUM COMPOUNDS, PRASEODYMIUM COMPOUNDS, MAGNETIZATION