Lonsdale, Kathleen (born Yardley) (1903-1971)

Irish X-ray crystallographer who was among the first to determine the structures of organic molecules. She derived the structure factor formulas for all space groups. Yardley was born in Droichead Nua, 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. As a pacifist, she was imprisoned for a month during World War II. In 1946 she became professor of chemistry and head of the Department of Crystallography at University College, London. 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. Lonsdale 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.