Few molecules are as iconic as benzene.

“Everyone loves the hexagon,” he says. katie duncanMichael Faraday, Postdoctoral Fellow in the History of Science at the Royal Institution first isolated benzene Just over 200 years ago. in 2025 essay for chemistry worldScience writer Philip Ball said that benzene’s brand recognition rivals that of DNA.

Although it is a benzene ring, found in nature—and in space-They are closely connected to human efforts to not only study the natural world but also to manipulate it at the molecular level.

The story of how benzene became everyone’s favorite hexagon is the story of how chemistry established itself as a science against the backdrop of industry and imperialism throughout the 19th century. This is also a story about the value of careful research, the importance of basic science, and how history will remember its contributions.

While it’s fun to celebrate benzene’s 200th anniversary, he says, focusing too much on a single discovery or person “overshadows how the science is done and who’s doing the science.” science historian katherine jacksonis currently writing a book on the history of benzene rings. It’s important to look at these moments through a broader lens and “be a little more realistic about what it takes to do science.”

The beginning of benzene

All things considered, the initial discovery of benzene “wasn’t the most important thing Faraday did. [but] That resonates with chemists,” he says, because of what happened next. James R. Felkelis a historian and curator of rare books at the Institute for the History of Science.

Faraday is best known for his discovery of electromagnetic induction, which is now considered more physics than chemistry. But at the time, the boundaries between academic disciplines were still largely fluid, and “very few people were doing science as a profession,” Fölkel says.

In the early 1800s, chemical research was still done by doctors and wealthy independents, but by the mid-20th century it would become a laboratory-based discipline, Jackson said.

Faraday was not independently wealthy. He spent seven years as an apprentice to a bookbinder before joining the Royal Institution in 1813, working under its then director, Humphrey Davy. Davie was an early pioneer in electrochemistry and was the first to separate sodium and potassium. Faraday became assistant director in 1821 and director of the laboratory in 1825, separating benzene the same year.

The discovery of benzene was made possible thanks to industry partnerships. A portable gas company asked Faraday to help identify the oily byproducts produced when producing lighting gas from whale oil and fish oil.

Faraday, a very thorough experimentalist, used fractional distillation to separate the components of petroleum. He calculated that it was composed of carbon and hydrogen in a 2:1 ratio, resulting in a unique clear liquid that he called the “bical bullet of hydrogen.” At the time, chemists’ understanding of atomic mass was still under construction, and the most popular model at the time placed the relative weight of carbon at 6.

He managed to obtain a liquid with a purity of over 99%. Given the technological limitations of the time, Duncan said, this is a testament to how good Faraday was at his laboratory work. “He fought oil and gas and got benzene.”

Faraday published the characteristics of hydrogen bicarburetors in June 1825. Philosophical Transactions of the Royal Society Then I moved on to other explorations. At the time, no one thought this was an important discovery, Felkel said. But it wasn’t until just a few decades later, thanks to the fad for coal tar and Victorian-era purple fabrics, that everything changed.

The dawn of the aromatics era

By 1833, Faraday’s mystery liquid had a new name. Benzene is derived from benzoic gum, a tree resin from Southeast Asia that was an early source of benzoic acid. As chemistry developed as an academic science, the analysis of medicinal alkaloids and other natural substances became a key way to demonstrate the value of the field, Jackson said. Another big push for chemistry in the mid-19th century was finding uses for coal tar. Benzene was found to be important on both fronts, but especially the latter.

Chemists discovered a way to obtain benzene from coal tar in 1845. Coal produces many other “aromatic” compounds, so named because they have similar odors. Industrial-scale production began a few years later.

The big break in aromatic chemistry occurred in 1856. At this time, 18-year-old William Henry Parkin accidentally invented the first synthetic dye, mauvaine, when he tried to make the antimalarial drug quinine from coal-derived aniline. The bright purple pigment was an immediate commercial success, proving that organic chemistry could be high fashion and high tech. From there, new chemical methods and new products rapidly accumulated.

As far back as 1862, Faraday became known as the father of aromatic chemistry. Parkin’s former mentor, August Wilhelm Hoffmann, pointed to Faraday’s “pure work” on benzene as the standard to which Royal Institution chemists should aspire.

By the end of the 19th century, research into aromatics was flourishing in academia and industry. Companies were eager to turn coal tar into synthetic dyes and pharmaceuticals such as aspirin. Chemists were able to determine the true molar masses of elements and derive accurate empirical formulas for organic compounds. Swedish pharmacologists had already found evidence of benzene’s carcinogenic properties.

However, the true structure of the molecule remained a mystery.

solve the structure

August Kekulé is often credited with elucidating the structure of benzene, a famous hexagon with alternating single and double bonds. The story goes that Kekule came up with this depiction of the molecule in 1865 after having a dream in which a snake ate its tail. But in reality, people continued to debate its structure for decades.

“Many great chemists spent many years of their lives figuring out the structure of benzene,” Jackson says. Kekule himself knew that the alternating bond structure could not fully explain how benzene and its aromatics behave in the laboratory. However, at a conference called Benzofest held in Berlin in 1890, German chemists united on Kekule’s ideas as the best theory available.

This situation remained more or less until the arrival of the Irish crystallographers. Kathleen Lonsdale Elucidated the crystal structure of hexamethylbenzene Thanks to Lonsdale, we now know that the ring at the center of the molecule is a flat hexagon with sides of equal length.

Lonsdale studied with William Henry Bragg at the Royal Institution and moved to the University of Leeds in 1927, where he completed research on hexamethylbenzene. Her research has given chemists a deeper understanding of molecular structure and electron delocalization.

“She had a very deep understanding of X-ray crystallography techniques and the underlying mathematics,” Duncan says. And she directly paved the way for future crystallographic discoveries, such as Dorothy Crowfoot Hodgkin’s solution of the structures of penicillin and vitamin B.₁₂ In the 1940s.

In a sense, Faraday and Lonsdale are a neat set of benzene origin stories. Both are talented experimental scientists working at the intersection of chemistry and physics, and despite a century of difference, both are connected to the same institution. One is largely remembered in history, the other is not.

Jackson says history is often sidelined in modern science education. But she believes that if we neglect understanding how a subject came into being, we lose something important. History helps us understand how we know what we know, and ultimately “the place of science in the world,” she says. It’s useful to know how we got here, especially given that today, “chemistry’s place in the world is in many ways very problematic.”

Benzene is an excellent case study for understanding chemistry’s place in the world. Benzene is “a great tool that helps chemists generate ideas in a variety of ways,” Duncan says. Scientists have used this to make fundamental discoveries, develop life-saving drugs, and create new materials that change the quality of people’s lives. But it’s also important to recognize the dark side of this iconic ring: its toxicity, its entanglement with the fossil fuel industry, and the presence of environmental pollutants.

Solving today’s scientific problems requires chemists who understand where those problems came from and how scientists of the past approached big problems, Jackson says. And anniversaries provide the perfect opportunity to think about just that.