Kathleen Lonsdale
Irish crystallographer who proved the benzene ring is flat.
Dame Kathleen Lonsdale was born Kathleen Yardley on 28 January 1903 in Newbridge, County Kildare, Ireland, and died on 1 April 1971. She worked as a crystallographer, campaigned for peace, and pushed for prison reform. In 1929, she used X-ray diffraction to study hexamethylbenzene, proving that the benzene ring is flat. In 1931, she became the first person to apply Fourier spectral methods when solving the structure of hexachlorobenzene. Over her career, she broke several barriers for women in science: in 1945 she was one of the first two women elected a Fellow of the Royal Society (alongside Marjory Stephenson), she became the first female professor at University College London, the first woman to lead the International Union of Crystallography, and the first woman to serve as president of the British Association for the Advancement of Science.
Her father, Harry Frederick Yardley, was the town postmaster in Newbridge, and her mother, Jessie Cameron, was a Baptist of Scottish descent. Kathleen was the youngest of ten children; four died in infancy. She attended St. Patrick’s National School in Newbridge, and her earliest memories included Church of Ireland services and Methodist Sunday school. Her father struggled with alcohol, which left the family short of money. As political unrest in Ireland grew, her mother separated from him and moved the family to Seven Kings, Essex, England in 1908, when Kathleen was five. Financial troubles forced her four older siblings to leave school early to support the family; her brother Fred had to turn down an educational scholarship, though he later became one of the first wireless operators. Her father moved to South Africa, returning occasionally, and died when she was 20.
From 1908 to 1914, Lonsdale attended Downshall Elementary school. She studied at Ilford County High School for Girls, then switched to Ilford County High School for Boys to take mathematics and science, which the girls’ school did not offer. In 1919 she entered Bedford College for Women, graduating in 1922 with the highest physics score ever achieved by a London University student. She earned a Master of Science in physics from University College London in 1924. One of her examiners, William Henry Bragg, was impressed enough to offer her a research position.
In 1924, she joined Bragg’s crystallography team at the Royal Institution. After marrying in 1927, she moved to the University of Leeds but kept in touch with Bragg. Between 1927 and 1932, while at Leeds, she started a family and set up X-ray equipment with a Royal Society grant. She balanced determining space groups with caring for her children. Leeds chemistry professor Christopher Ingold suggested she study the crystal structures of hexamethylbenzene and hexachlorobenzene; in both cases she showed the molecules were flat and hexagonal, settling a long debate about benzene’s structure. Her husband, Thomas Lonsdale, was a textile chemist who supported her work, encouraging her to work from home and to return to the lab when opportunities arose. He worked at the Silk Research Association in Leeds after their marriage.
In 1934, Lonsdale returned to the Royal Institution as a researcher with Bragg. She received a DSc from the University of London in 1936. She was a pioneer in using X-rays to study crystals. In 1945, she and biochemist Marjory Stephenson became the first two women elected Fellows of the Royal Society. In 1946, she went back to University College London as a reader. In 1949, she was appointed Professor of Chemistry and head of the Department of Crystallography at UCL—the first woman professor there. She held the post until 1968, when she became professor emeritus.
An avid table tennis player, Lonsdale used ping-pong balls to demonstrate molecular structures to her students. One model, of the silicate group Si2O5, is in the Science Museum collection. Later in her career, she studied stones and minerals that form in the human body, such as kidney stones and gallstones. Some of her crystallographic models are also held by the Science Museum in London.
- born
- 28 January 1903, Newbridge, County Kildare, Ireland
- died
- 1 April 1971, aged 68
- field
- Crystallography
- nationality
- Irish
- known_for
- Proving the benzene ring is flat; first use of Fourier spectral methods in cryst
Lore & Background
Kathleen Lonsdale was born Kathleen Yardley in Newbridge, County Kildare, Ireland, the youngest of ten children, four of whom died in infancy. Her father had issues with alcohol, and the family moved to Seven Kings, Essex, England in 1908 when she was five. She attended Downshall Elementary school from 1908 to 1914, then studied at Ilford County High School for Girls, transferring to Ilford County High School for Boys to study mathematics and science because the girls' school did not offer these subjects. In 1919 she began studying at Bedford College for Women, graduating in 1922 with the highest score in physics that any student at London University had ever achieved. She completed an MSc in physics from University College London in 1924, and William Henry Bragg offered her a research position. In 1924 she joined Bragg's crystallography research team at the Royal Institution. Following her marriage in 1927 to Thomas Jackson Lonsdale, she moved to the University of Leeds, where she set up X-ray equipment using a grant from the Royal Society and balanced her work on space groups with looking after her children. At Leeds, Professor Christopher Ingold suggested she investigate the crystal structures of hexamethylbenzene and hexachlorobenzene; in both cases she showed the molecules to have a planar, hexagonal structure, settling the long-standing dispute about the structure of benzene. She returned to work with Bragg at the Royal Institution in 1934, and was awarded a DSc from the University of London in 1936. In 1945 she was one of the first two women elected a Fellow of the Royal Society. She returned to University College London in 1946 as a reader, and in 1949 was appointed Professor of Chemistry and head of the Department of Crystallography, the first woman professor at UCL. As a keen table tennis player, she used ping pong balls to demonstrate molecular structures; one model of the silicate group Si2O5 is in the Science Museum collection. Lonsdale became a Quaker in 1935, simultaneously with her husband, and was a committed pacifist and Sponsor of the Peace Pledge Union. During the Second World War she served a month in Holloway prison because she refused to register for civil defence duties or to pay a fine for refusing to register. This experience led her to become a prison reform activist, and she joined the Howard League for Penal Reform. In 1953 she delivered the Swarthmore Lecture titled 'Removing the Causes of War'. She was appointed the first secretary of the Churches' Council of Healing by the Archbishop of Canterbury William Temple. Lonsdale died on 1 April 1971, aged 68, from an anaplastic cancer, possibly related to her exposure to X-rays.
Reader's Guide
Kathleen Lonsdale's significance rests on her foundational crystallography work and her pioneering role for women in science. Her 1929 proof that the benzene ring is flat, using X-ray diffraction on hexamethylbenzene, resolved a long-standing dispute in organic chemistry. Her 1931 use of Fourier spectral methods while solving hexachlorobenzene was a first in the field. She was one of the first two women elected a Fellow of the Royal Society in 1945, the first female professor at University College London, the first woman president of the International Union of Crystallography (1966), and the first woman president of the British Association for the Advancement of Science (1967). Her pacifism led to a month in Holloway prison during the Second World War, which turned her into a prison reform activist and member of the Howard League for Penal Reform. She was also the first secretary of the Churches' Council of Healing. Her legacy includes the carbon allotrope lonsdaleite named in her honor, buildings at University College London, the University of Limerick, Dublin City University, and Maynooth University, and a Royal Irish Academy chemistry prize named after her since 2000. A blue plaque was unveiled at her childhood home in Seven Kings, London on 1 April 2021.
Did You Know?
- She proved the benzene ring is flat in 1929 by using X-ray diffraction to elucidate the structure of hexamethylbenzene.
- She was the first to use Fourier spectral methods while solving the structure of hexachlorobenzene in 1931.
- She was one of the first two women elected a Fellow of the Royal Society in 1945, along with Marjory Stephenson.
- She served a month in Holloway prison during the Second World War for refusing to register for civil defence duties.
- The carbon allotrope lonsdaleite, a rare harder form of diamond found in meteorites, was named in her honor.
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