Vitriol

Vitriol is a historical term used for a family of sulfate minerals and for sulfuric acid. In medieval and early modern chemistry, vitriol referred to hydrated metal sulfates, most notably blue vitriol (copper(II) sulfate), green vitriol (iron(II) sulfate), and white vitriol (zinc sulfate). The expression oil of vitriol designated concentrated sulfuric acid, obtained by distillation of certain sulfates.

Etymology: The word derives from Old French vitriol, from Latin vitriolus, from vitrum “glass.” The name likely reflects the glassy crystals these salts form and the caustic, glass-like reputation of the acids derived from them.

History and use: Vitriols were widely employed in dyeing, printing, ore processing, and various chemical applications in antiquity and the early modern era. Alchemists and early chemists used the term to describe sulfates and the acids produced from them. The common names blue vitriol, green vitriol, and white vitriol persisted into the 19th century to distinguish copper, iron, and zinc sulfates, respectively.

Modern usage: The term vitriol is largely obsolete in contemporary chemistry, though the historical names remain in reference to the corresponding sulfates. The adjective vitriolic survives in language to describe harsh or caustic criticism, reflecting the corrosive associations of the minerals and acids.

Safety: Copper, iron, and zinc sulfates are chemical compounds with toxic and irritating properties; sulfuric acid is highly corrosive. Proper handling, storage, and safety measures are essential when working with these materials.