A series of neutral organophosphorus compounds including trialkylphosphats, dialkyl alkylphosphonate, alkyl dialkyl phosphinate, trialkyl phosphine oxide and alkyl esters of phosphorus acid have been separated by reversed phase chromatography on acetylated paper.The R_f values vary with the type of compounds and are closely rolatod to the number of carbon atoms of the alkyl groups, the nature of the mobile phase and the acetyl number of the paper.The molecnlar weight and the polarity of the title compound as represented by the summation of the group negativities(∑X)are the determinants in th)ir behavior on paper chromatography.When the R_f values rare plotted either against bhe number of carbon atoms of alkyl groups for homologous series, or against the ∑X of the compounds under investigation, straight lines result in both cases.A prediction of the R_f value of an unknown compound of phosphorus can thus be performed.