[C17H20N2I]3{RE[N(CH2CO2)3]2}.nH2O (C17H20N2I = 3,6-di(dimethylamino) dibenzopyriodonium; RE = La, Eu, Er, n = 3; RE = Ce-Nd, Tb-Ho, Tm, Yb, Y, n = 4; RE = Sm, Gd, Lu, n = 5) were prepared The complex salts were characterized by x-ray powder diffraction TG-DTA, IR, UV, 1H NMR and molar conductances. The antitumor activity of the La complex was studied on transplanted mouse tumor S180 in vivo and mouse lymphocytic leukemia cell (L1910) in vitro. The results showed that the La complex is more effective than its precursors. The Dy complex is monoclinic, space group P212121, a 1.5154(2), b 1.8234(3), c 2.4010 ? Z = 4, dc = 1.751 g cm-3.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, ANTICARCINOGEN, INFRARED SPECTROPHOTOMETRY, X-RAY DIFFRACTION ANALYSIS, YTTRIUM COMPLEX, NITRILOTRISACETIC ACID P, HOLMIUM COMPLEX, RARE EARTH METAL COMPLEX, CERIUM COMPLEX, THERMOGRAVIMETRY