Abstract: Based on the principle of the sum of inducted polarity vectors proposed by us and its successful applications in explanations of the stabilities of isomers and design of a new scheme for calculation of the enthalpies of formation of alkanes, we have designed a new scheme with 5 parameters for the calculation of the standard enthalpies of formation of polychloroalkanes. Compared with the Group Additivity Scheme with 9 parameters, this new scheme has a higher calculation accuracy(its prediction errors are even lower than the experimental deviations). This new scheme contains less parameters and thus can be extended to calculate theoretically the standard enthalpies of formation of alkane derivatives with some different hetero atoms on a carbon atom.

Key words: Standard enthalpy of formation, Sum of inducted polarities, Polychloro