The element oxygen, represented by the symbol O and atomic number 8, is fundamental to life on Earth, driving processes from human respiration to combustion. While its significance is universally recognized today, the specific origin of its name is not immediately obvious from its atmospheric role. The word is a historical relic from a revolutionary era in 18th-century chemistry. The name arose from independent discoveries and a single scientific misinterpretation that shaped modern scientific language.
The Initial Isolation of the Element
The element was first isolated by two chemists working separately in Europe during the 1770s. Swedish pharmacist Carl Wilhelm Scheele produced the gas around 1772 by heating substances like mercuric oxide and saltpeter. Scheele did not publish immediately and called the material “fire-air” (Feuerluft) due to its ability to support intense combustion.
In England, chemist Joseph Priestley independently isolated the same gas on August 1, 1774, by focusing sunlight onto mercuric oxide. Priestley published his results first, but interpreted his findings using the prevailing phlogiston theory. He named the gas “dephlogisticated air,” believing it was common air stripped of the hypothetical substance phlogiston.
Lavoisier, Etymology, and the Name
French chemist Antoine Lavoisier recognized that the gas discovered by Scheele and Priestley was a distinct chemical element, not just a variant of common air. Lavoisier conducted careful experiments proving this new substance was consumed during both combustion and respiration. His work systematically dismantled the phlogiston theory, creating a need for a new, descriptive nomenclature for the elements.
In 1777, Lavoisier coined the name oxygène from two ancient Greek root words. The first part, oxys, translates to “sharp” or “acid,” referring to the taste of many acids he studied. The second part, -genēs, means “producer” or “former.”
The name oxygen literally means “acid-former” or “acid-producer.” This term was part of Lavoisier’s systematic reform of chemical language, designed to reflect the composition of chemical substances. The selection was based on a specific chemical principle Lavoisier deduced, though it was ultimately incorrect.
The Misconception That Drove the Naming
Lavoisier named the element “acid-former” based on a powerful observation: the combustion products of non-metals like sulfur and phosphorus formed acidic solutions when dissolved in water. Lavoisier hypothesized that this new element was the universal component necessary for all acids.
He believed oxygen was the sole element responsible for imparting acidic properties to any compound it formed. This theoretical framework influenced his entire system of chemical classification and nomenclature. However, this hypothesis was later proven flawed, as not all acids contain oxygen.
A clear counterexample is hydrochloric acid (HCl), which is composed only of hydrogen and chlorine and contains no oxygen atoms. Despite the error being recognized by chemists like Sir Humphry Davy in the early 19th century, Lavoisier’s influence ensured the name “oxygen” remained firmly established. The name, born from an incomplete understanding of acid chemistry, persisted as the globally accepted term for the element.