Pauling’s Second Rule and Its Applications: From Inorganic Compounds to Understanding the Function of ATP

Abstract

Pauling’s five rules for ionic crystals emerged as a generalization of the first experimentally determined crystal structures of inorganic compounds (primarily minerals). It was later discovered that the second rule (the rule of bond valence balance) is particularly powerful and universal. This essay explains how this rule can be used to explain very easily the differences in the chemistry of entire classes of chemical compounds (e.g., silicates and phosphates), as well as to elucidate the function of ATP as the universal energy currency for all life forms.