Synergistic Effects in Extraction Substrates (Ⅱ)

Based on the steric effect,ligand packing around the uranyl equatorial plane should be neither overcowded nor undercrowded. The sum of Ligand's Fan Angle(FAS)around the uranyl equatorial plane provides a useful criterion for estimating steric crowding.FAS of UO₂(OAc)Br(TBP)₂ is 180°indecating the most favorable packing. It is therefore expected that a higher extraction efficiency should coincide with the formation of the more stable complex. The above speculation was confirmed by extraction of uranyl ion in the substrates of sodium acetate-acetic acid and sodium bromide. Keeping the total concentration of substractes constant, synergistic extraction is found at l:10 acetate to bromide ratio. The extracted complex was proved to be UO₂(OAc)Br(TBP)₂ by using the slope method.