Antoine Lavoisier’s combustion experiments identified oxygen as the gas essential for burning.
In the late eighteenth century, Lavoisier heated substances such as mercury in sealed vessels and measured the gases and solids before and after heating. He found that combustion involved combination with a component of air, rather than the release of a mysterious substance called phlogiston.
Lavoisier named this component oxygen, from Greek roots meaning acid-former, although that name reflects an incorrect belief that oxygen was present in all acids. His quantitative measurements also demonstrated conservation of mass in chemical reactions.
Joseph Priestley had isolated the gas earlier, calling it dephlogisticated air, but Lavoisier correctly interpreted its role in combustion and respiration. The work helped establish modern chemical nomenclature and experimental chemistry.