Americium extraction by vinylene diphosphine dioxides

The extraction is studied of americium (3) with tetravinylene and tetratolylvinylenediphosphine cysdioxides from nitric acid solutions. The formation of AmS2(NO3)3 disolvates was established, where S represents the extragent molecule. The high values of the extraction constants (108 and 1.7x109, respectively) point to a bidentate coordination of Am. The action of a spatial factor (a rigid bridge) results in an appreciable enhancement of extraction. The effect is becoming more pronounced at the combined action of a spatial and an electron factor (a tolyl dioxide)