The structure maker-structure breaker categories for aqueous electrolytes signify strength of Lewis acidity/basicity relative to water

Small, dissolved ions are commonly categorized as "structure makers" or "structure breakers" based on the implicit assumption that they alter the structure of bulk water. Many authors have questioned the structure maker-structure breaker lexicon, even though the categorization correctly identifies the effects of ions on transport properties. A plethora of studies indicate that the largest impact of ions on water structure occur within one or two water molecules of the ions. The short-range nature of these specific ion effects led the present author to determine if these categories could be defined by ions' Lewis acidities or basicities relative to water using the bond-valence model. This study found that structure breaking ions are those whose Lewis acidities or basicities were much weaker than water and thus bound water less strongly than water binds to itself. Structure makers are those ions whose Lewis strength was much greater than water's, leading to stronger binding of water to the ions than water binds to itself. Ions can thus be categorized by their Lewis strength rather than ambiguous structure making or breaking capability.