Thermodynamical and physical aspects of the occurrence of absolutely pure substances

A possibility of the existence of absolutely pure substances is related to a number of aspects: the trends in the changes of their entropy and the heat of formation, their state of aggregation, the lowest quantitative limit of their existence and detection, and their isotopic composition. The entropy of the substances changes with a faster tempo (by logarithmic law) than their heat of formation does (by parabolic law). Hence a conclusion is made on the impossibility of an absolute purification of the substances (mainly in the solid state).