Lonsdale, Kathleen (1903–1971)

Irish X-ray crystallographer who developed several technologies for the study of crystal structures. She was among the first to determine the structures of organic molecules, and the first to confirm the hexagonal arrangement of carbon in benzene compounds. She derived the structure factor formulas for all space groups. In 1945 she was the first woman to be elected to the Royal Society and she was made DBE in 1956.

Yardley was born in Newbridge, County Kildare, but moved with her family to England in 1908. After graduating from Bedford College for Women in London, she joined the research team of W H Bragg at University College, London, and later at the Royal Institution. Between 1927 and 1931 she worked at Leeds and then returned to the Royal Institution.

She was interested in X-ray work at various temperatures and thermal motion in crystals. She also used divergent beam X-ray photography to investigate the textures of crystals. She studied solid-state reactions, the pharmacological properties and crystal structures of methonium compounds, and the composition of bladder and kidney stones.

At Leeds she used a grant from the Royal Society to buy an ionization spectrometer and electroscope and solved the structure of crystals of hexamethylbenzene.

As a pacifist, Lonsdale was imprisoned for a month during World War II. After her election to the Royal Society, she became professor of chemistry and was appointed head of the department of crystallography at University College, London 1946–68. In 1968 she became the first woman president of the British Association for the Advancement of Science.