[en] The possibility of quantitative describing the effect of the concentration of the aqueous phase components on extraction of some trivalent actinoides and lanthanoides from LiCl solutions with various nucleophilic agents has been shown. The description has been performed with the use of linear equations of the lg D=lg D₀+PSI EAPh type derived from linear relations between free energy values (LRE) and the law of mass action. In this equation D is the distribution coefficient of the element in the given system, D₀ the same coefficient in the system with a reference composition of the aqueous phase, PSI is the sensitivity coefficient constant for given series of the extraction systems; EAPh is the parameter independent of the extragent type and characterizing only the effect of quantitative composition of the aqueous phase on extraction of the element. It has been shown that upon extraction from LiCl solutions one EAPh scale describes the behaviour of all trivalent lanthanoides and actinoides considered