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Dame Kathleen Lonsdale DBE FRS

Kathleen Lonsdale was made one of the first female fellows of the Royal Society for her pioneering work in crystallography.

Photograph of Dame Kathleen Lonsdale

Kathleen Lonsdale is not particularly well-known outside her own subject, despite playing a fundamental role in establishing the science of crystallography and scoring several important firsts during her scientific career. She had a profound influence on the development of X-ray crystallography and related fields in chemistry and physics. Very few have made so many important advances in so many different directions. 
Kathleen was born in Newbridge, County Kildare, Ireland. An academically gifted child, Kathleen was forced to take classes in chemistry, physics and mathematics at the local boy’s school because the girl’s school did not teach these subjects. She continued to excel and in 1922, Kathleen graduated from Bedford College for Women, part of the University of London, with the highest marks in physics for 10 years. As a result of her successes, Kathleen came to the attention of Sir William Henry Bragg, a pioneer of X-ray diffraction and a physics Nobel Laureate, and he invited her to join his research group at University College London (UCL).
Sir William was an inspiring supervisor and Kathleen wrote of him: 
“He inspired me with his own love of pure science and with his enthusiastic spirit of enquiry and at the same time left me entirely free to follow my own line of research.”  

An important discovery

Kathleen used X-ray diffraction to study the structure of molecules and in 1929, she published her pivotal paper on the structure of the benzene ring in hexamethylbenzene.
 Professor K. N. Trueblood said of her discovery: 
“Her experimental determination of the structure of the benzene ring by X-ray diffraction, which showed that all the ring C-C bonds were of the same length and all the internal C-C-C bond angles were 120 degrees, had an enormous impact on organic chemistry.”
In addition to discovering the structure of benzene and hexachlorobenzene, Kathleen also worked on the synthesis of diamonds. This aspect of her work was recognised when Lonsdaleite, a form of diamond found only in meteorites, was named after her.

Blazing a trail for other women scientists to follow

Kathleen Lonsdale was awarded a DSc by University College London in 1936, and in 1945, she and Marjory Stephenson became the first women fellows of the Royal Society, ending a 285 year-old tradition of the fellowship not admitting women. In 1949, she also became the first female professor of chemistry and head of the Department of Crystallography at University College London, a position Kathleen held until 1968, after which she was named professor Emeritus.

Her friend and contemporary, the 1964 chemistry Nobel Laureate Dorothy Hodgkin, said of Kathleen Lonsdale: 
“There is a sense in which she appeared to own the whole of crystallography in her time.”
Words by Andrea Banham
Image © Godfrey Argent Studio 
Published August 2013

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