Edward Frankland

Edward Frankland introduced the concept of valence—which he called "combining power"—in 1852, proposing that each element forms a characteristic and definite number of bonds with other atoms. This was a foundational idea in structural chemistry that preceded and influenced the later development of structural theory by Butlerov, Kekulé, and Couper.

Frankland's synthesis of diethylzinc in the mid-19th century was one of the first preparations of an organometallic compound, demonstrating that metals could form direct bonds with carbon atoms. This work helped establish organometallic chemistry as a distinct field of study.

Frankland published his concept of combining power in 1852, making it one of the earliest theoretical frameworks for understanding chemical bonding. The idea was developed further by August Kekulé, Archibald Couper, and Aleksandr Butlerov later in the same decade.

In addition to his theoretical chemistry, Frankland was appointed to analyze London's water supply and developed systematic methods for detecting contamination. His work in environmental chemistry helped establish the scientific basis for Victorian-era public health standards for drinking water.