The study on solvent extraction of rare earth elements from nitric acid solutions with triphenylphosphine oxide (TPPO), mixture of TPPO + PC88A (2-ethylhexyl 2-ethylhexyl phosphonic acid) has been studied and the influence of various factors such as concentrations of (TPPO), mixture of TPPO and PC88A, nitric acids and rare earth elements on the distribution coefficient also been studied. The formulation of extracted complex of yttrium with TPPO + PC88A has been presented by using the method of infrared spectroscopy (IR), UV - Vis spectra and Inductively Couple Plassma - Atomic Emission Spectrometry (ICP-AES) analysis. Result shown that yttrium could be complexes with mixture of TPPO + PC88A and formulation of extracted complex of yttrium with mixture of TPPO + PC88A were Y(PC88A)3
2TPPO.