C2H52Pb

C2H52Pb is the chemical formula for tetraethyllead, often abbreviated as TEL. It is an organolead compound that was historically used as a gasoline additive. Its primary function was to increase the octane rating of gasoline, preventing engine knocking and allowing for higher compression ratios. This improved engine performance and efficiency.

Tetraethyllead was first synthesized in 1921 by Thomas Midgley Jr. and Charles Kettering. Its widespread adoption in gasoline began in the 1920s and it became a common additive globally for decades. However, concerns about its toxicity and environmental impact led to its gradual phase-out. Lead is a neurotoxin that can cause significant health problems, particularly in children, affecting brain development and cognitive function. The exhaust from vehicles using leaded gasoline released lead particles into the atmosphere, contaminating soil, water, and air.

Due to these environmental and health risks, many countries began phasing out leaded gasoline in the late 20th century, with a global ban on its production and use for road vehicles by 2021. While its use in gasoline has largely ceased, tetraethyllead might still find limited applications in aviation gasoline (avgas) and in some specialized industrial processes, though these uses are also under scrutiny and being replaced by alternatives.