Birth Date: 8 November 1926
Place of Birth: Terril, Iowa, United States
Nationality: American
Occupation/Field of Study An American nuclear chemist who worked with transuranium elements and made important discoveries about nuclear fission.


KEYWORDS: Nuclear Chemistry, Chemistry, Science, Woman, Darleane C. Hoffman, Seaborgium, researcher, innovator



Darleane C. Hoffman is one of the most appreciated scientists in nuclear chemistry. Her most visible discovery is connected with her mentor, Glenn T. Seaborg. Darleane was part of the group of researchers that discovered “seaborgium”, a new element which they also named. In 1971, she discovered primordial plutonium in nature; a very significant discovery, since remnants of the element were found in the field, resulting from the plutonium bomb which was dropped over Nagasaki in 1945¹ (p. 103).

At the time Darleane was finishing her studies, it was normal for women to choose to have either a career or a family, but she wanted to have both. Social pressure did not stop her from studying and analysing evasive elements, such as transuranium elements. She published her discovery of small amounts of a plutonium isotope in a rock formation dated as being several billion years old, even though, prior to this, it was believed that heavy elements did not exist in nature.⁵

Darleane C. Hoffman was an outstanding scientist who was also interested in gender issues. For instance, during her academic visit to Norway, she noticed that Norwegian women were treated much more equally than those in the United States. She was surprised that women were more independent, and she decided to continue to promote this attitude in the social and academic sphere¹ (p. 105).

Darleane C. Hoffman was the second woman to be awarded the Priestley Medal, the highest honour of the American Chemical Society.⁶ She received many other recognitions and awards during her research, worked for several government advisory boards, and wrote more than 200 research papers on the chemistry topics related to heavy elements and nuclear chemistry.⁶



Darleane C. Hoffman was born in Terril, north-western Iowa, on the 8th November 1926. Her father was a school principal and maths teacher, something which had an impact on Darleane’s career orientation. Furthermore, she often worried that other students would think she was being favoured, and so she did not even dare to ask for his help with homework³ (p. xxiii). After high school, she enrolled in the Faculty of Arts at Iowa State College but soon changed her major to chemistry. She was excited to study chemistry, one of the reasons being that her chemistry professor was to be Nellie Nylor. She was an inspiration to Darleane and a role model for many young women who had been taught that a woman had to choose between either a career or a family.⁵ However, Darleane was an exceptional student with the highest grade averages. After graduating from university, she continued her studies and finished her PhD specialising in nuclear chemistry in 1951¹ (p. 103). It was at high school that she met her future husband Marvin Hoffman, and they married after she completed her doctorate. From then on, she held several positions in different national laboratories around the country. She was a senior advisor and charter director for the G. T. Seaborg Institute at the Lawrence Livermore National Laboratory.⁶ Afterward she held a position at Oak Ridge National Laboratory in Tennessee for ayear and then followed her husband to Los Alamos National Laboratory in New Mexico¹ (p. 103). During their work, Darleane and her husband expanded their family and had two children. It should be noted that, during this time, Darleane never stopped working. “They had a woman who came every day to take care of children until her mother moved there to live nearby in 1964, and from then on she helped”¹ (p. 103).

Source: Berkeley College of Chemistry

The next step in Darleane’s career after working on the spontaneous fission of elements in Los Alamos, was at Berkeley. Between 1978 and 1979, she worked at the University of California at Berkeley with a Guggenheim fellowship in Glenn Seaborg’s group¹ (p. 103).

Darleane and her family finally moved to Berkeley in 1984 and she became the leader of the Heavy Element and Radiochemistry Group.⁶ While studying and working later down the line, she faced many challenges regarding gender discrimination. When she started her career as a professor, her husband told her that she should not be amazed if “she did not get too many graduate students because probably some of the young men would not want to work for a woman”⁴ (p. 163). Before this, she had received a discriminative response from the radiochemistry laboratory where she was attempting to get a job: “I am sorry, but we don’t hire women in that division! […]”¹(p.103). This greatly offended her and, after this happened, she never trusted personnel departments again.

However, the plutonium-244 discovery was Darleane Hoffman’s greatest achievement. It was her most publicised scientific achievement, although it was not her only one¹ (p. 105). Several other significant discoveries made by Darleane included that of symmetric mass division in spontaneous fission and that of heavy, short-lived fermium isotopes¹ (p. 105).

An extremely important phenomenon Darleane was willing to address was the reality with regards to unequal remuneration of women and men. During her time as a division leader at Los Alamos, she participated in the management of payment and financial distribution. Regarding the concerns about women not receiving equal payment to men in equivalent positions, each division received a sum of money to make pay gaps smaller¹ (p.105). “They [we] distributed the money according to merit among the women and Darleane [I] felt like that this was one of those win-win situations”¹ (p. 106). Nevertheless, this was not her only concern. The most important, in her opinion, was “to investigate the climate and the concepts of tenure and why so many women choose not to even apply for positions at the major research universities in the U.S.”¹ (p. 106).



Darleane was part of the greatest discoveries relating to heavy elements; one of the most visible of which definitely being that of the discovery of primordial plutonium in nature. She worked with Lise Meitner and Otto Frisch on the remnants of plutonium in nature, after they interpreted the nuclear fission experiment of uranium.¹ (p. 104) Later on Seaborg and his associates artificially produced plutonium, “which then played a conspicuous role in the development of atomic bombs”¹ (p. 103).



The beginning Home Economics Chemistry at Iowa State was taught by Prof. Nellie Naylor, and largely due to her outstanding teaching I found myself more interested in Chemistry than anything I had ever studied. She had a way of making it all seem so beautifully logical as well as relevant to a host of everyday problems. Consequently, I decided by the second quarter that I would switch my major to Chemistry. This somewhat unconventional choice caused my Applied Art Counselor to ask me, “Do you really think chemistry is suitable profession for a woman?”! I replied that I was quite sure it was.

Preface of: Hoffman, C. Darleane / Albert Ghiorso / Glenn T. Seaborg (2000), The Transuranium People: The Inside Story, London, Imperial College Press.


Once in Los Alamos, I immediately started calling the personnel department to ask about my job in the Radiochemistry Group of the Test Division and they told me, “There must be some misunderstanding, we don’t hire women in that Division.” Having never before run into such discrimination, I was totally taken aback and asked them to please try to circulate my application and find out where my job was supposed to be, but to no avail.

Preface of: Hoffman, C. Darleane / Albert Ghiorso / Glenn T. Seaborg (2000), The Transuranium People: The Inside Story, London, Imperial College Press.


I found Norwegian women were treated much more equally than women in the U.S. at that time. It was all right for women to go out to dinner alone but men also didn’t open doors for them, etc. However, if you asked for help it was willingly given. I learned a great deal and developed a much more independent attitude socially and scientifically after our year there.

Hargittai, Magdolna, (2015), Women Scientists: Reflection, Challenges, and Breaking Boundaries, New York, Oxford University Press. (p. 105)



1978: Guggenheim Fellowship
1983: the first woman to be awarded with ACS Award for Nuclear Chemistry
1990: Garvan-Olin Medal
1997: National Medal of Science
2000: the second woman to be awarded with Priestley Medal, the highest honour of the American Chemical Society.



Hoffman, C. Darleane, (1980), Nuclear Properties of Mendelevium, Los Alamos National Laboratory.

Hoffman, C. Darleane / Albert Ghiorso / Glenn T. Seaborg (2000), The Transuranium People: The Inside Story, London, Imperial College Press.

Nitsche, Heino / Darleane C. Hoffman / Ralf Sudowe / Jon M. Schwantes / Charles M. Folden (III.) (2005), Neuron Capture Experiments on Unstable Nuclei, United States, National Nuclear Security Administration.



  1. Hargittai, Magdolna, (2015), Women Scientists: Reflection, Challenges, and Breaking Boundaries, New York, Oxford University Press.
  2. Hargittai, Istwán / Magdolna Hargittai (2006), Candid science VI: more conversations with famous scientists, London, Imperial College Press.
  3. Hoffman, C. Darleane / Albert Ghiorso / Glenn T. Seaborg (2000), The Transuranium People: The Inside Story, London, Imperial College Press.
  4. Hargittai, Balazs / Magdolna Hargittai / Istvan Hargittai (2014), Great Minds: Reflections of 111 Top Scientists, New York, Oxford University Press.
  5. Chemical Heritage Foundation, Hoffman (last updated November 3, 2015), <> (last accessed 15 Nov. 2017)
  6. Yarris, Lynn (2000), Chemists Award Darleane Hoffman Highest Honor in Their Field, Science Beat, <> (last accessed 24 Nov. 2017)





Release Date: