AbstractThorium nitrate was conductometrically titrated with malonic, succinic, adipic acids in aqueous solutions and azeleic and sebacic acids in alcoholic solutions, respectively. The composition and electrolytic behavior of thorium‐malonate system were investigated by conductometric and pH measurements. The formation of Th(CH2(COO)2)2was observed in the conductometric titrations of thorium nitrate with sodium and ammonium malonates, while that of the complex ion, (Th(OOC.CH2.‐COO)4)−4, in the reverse titrations. The approximate solubility product constant of the former is estimated from the results of pH measure