“Chemical” domains of definition of mathematic relations in organic chemistry

Abstract

The mathematic relations used in chemistry describe the processes with participation of various substances and the variations in the properties of chemical compounds. For the problems of the second type especially widely appearing in organic chemistry, introduction of concept of the chemical domains of definition of such relations, i.e. the scope of molecular structures in the domain for which application of these relations provides the maximum accuracy of obtained estimates, is expedient. By examples of some physical and chemical constants, including chromatography retention indices it, is shown that increase in the accuracy of the calculation equations can be reached not due to their complication, but by ascertaining definition of the chemical domains of their application. On the other hand, examples are demonstrated where the variation in the chemical domains of definition while the equations themselves remain unchanged open principally new opportunities of their application. Unlike mathematic domains of definition, their chemical equivalents cannot be revealed by the formal analysis of mathematic formulas. Solution of such problems, as a rule, requires computational checking of their applicability for compounds belonging to various groups.