. . "R1 and R2 are preferably alkyl groups as in N-alkylalkanohydroxamic acids, but can contain aromatic, halogen or other groups, provided that the compounds are water insoluble and the groups do not unduly interfere with functionality as extractants for gallium Exemplifications of R1 and R2 include linear, branched or cycloaliphatic groups although in the case of such cycloalkyl groups as cyclohexyl," . . .