A study has been made of the extraction of microamounts of caesium from the aqueous phase into 28 organic solvents in the
presence of sodium dipicrylaminate and nitrate, and the extraction of macroamounts of ceasium and rubidium dipicrylaminates
from nitrobenzene and nitromethane into some other organic solvents. The equilibrium constants of the reaction Cs
were determined and a correlation with the water content of the organic phase has been discussed.