CONCLUSIONS 109 BIBLIOGRAPHY 111 115 iv LIST OF TABLES = Xj^(M,N)/X^(M,N) . X^(L,M,N) -total molarity of lanthanides in the equili brated aqueous phase for a ternary system L,M,N. Y^(L,M,N) -total molarity of lanthanides in the equili brated organic phase for a ternary system L,M,N. Xj^(L,M,N) -equilibrium molarity in the aqueous phase of species M for a ternary system L,M,N. yj^(L,M,N) -equilibrium molarity in the organic phase of species M for a ternary system L,M,N. N" (L,M,N) -mole fraction of species M in the equilibrated M. ^ A aqueous phase for a ternary system L,M,N = Xj^(L,M,N)/X^(L,M,N) . ^ -concentration separation factor of species M with respect to N. ^ -organic molarity of lanthanide M assuming ideal behavior (no interaction) in a multicomponent extraction system -partial extractability. -total organic molarity assuming ideal behavior analogous to Raoult's Law for ideal solutions. Ay^ -deviation from ideality of the organic con centration of lanthanide M. = xi deviation from ideality of the total organic molarity. = Ay^ + Ay^ +... etc.