Chadwick Alma Tolman (October 1938 – April 6, 2024) was an American chemist. He obtained his B.S. in Chemistry from

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...

. He earned his Ph.D. in Chemistry as a microwave spectroscopist from

U.C. Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant univ ...

under the guidance of William Dulaney Gwinn.

Biography

Tolman joined

DuPont Central Research In 1957, the research organization of the Chemicals Department of E. I. du Pont de Nemours and Company was renamed Central Research Department, beginning the history of the premier scientific organization within DuPont and one of the foremost indu ...

in 1965. His early work was on late transition metal complexes with phosphorus ligands. The

Tolman cone angle In coordination chemistry, the ligand cone angle (a common example being the Tolman cone angle or ''θ'') is a measure of the steric bulk of a ligand in a transition metal coordination complex. It is defined as the solid angle formed with the met ...

and

Tolman electronic parameter The Tolman electronic parameter (TEP) is a measure of the electron donating or withdrawing ability of a ligand. It is determined by measuring the frequency of the A1 C-O vibrational mode (ν(CO)) of a (pseudo)-C3v symmetric complex, Ni(CO)3by infr ...

are named after him. In 1972, he proposed the 16 and 18 electron rule, extending

Irving Langmuir Irving Langmuir (; January 31, 1881 – August 16, 1957) was an American chemist, physicist, and engineer. He was awarded the Nobel Prize in Chemistry in 1932 for his work in surface chemistry. Langmuir's most famous publication is the 1919 art ...

's 18-Electron rule to include the many examples of stable 16 electron square planar d⁸ complexes. Later work focused on the activation of C-H bonds by transition metal complexes and free radical oxidation of

cyclohexane Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohexan ...

for the production of

adipic acid Adipic acid or hexanedioic acid is the organic compound with the formula (CH2)4(COOH)2. From an industrial perspective, it is the most important dicarboxylic acid: about 2.5 billion kilograms of this white crystalline powder are produced annually, ...

, an intermediate in the manufacture of

nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...

. Tolman was instrumental in the founding of the Delaware Science Alliance and took a year's leave of absence from DuPont to serve as Chair of the Coordinating Committee to help make the Alliance self-sustaining. The primary goal of the Science Alliances was to link scientists interested in education to teachers looking for help in the classroom. Programs include an Elementary Science Olympiad, workshops for volunteers and elementary teachers, summer fellowships in local industry for secondary teachers, and classroom visits and demonstrations by industrial scientists. Upon retirement from DuPont in 1996, Tolman taught at

Delaware Technical & Community College Delaware Technical Community College (previously Delaware Technical & Community College, also known as DTCC, Delaware Tech, or Del Tech) is a public community college in the U.S. state of Delaware. Delaware Tech is an open admission institution ...

and

University of Delaware The University of Delaware (colloquially UD or Delaware) is a public land-grant research university located in Newark, Delaware. UD is the largest university in Delaware. It offers three associate's programs, 148 bachelor's programs, 121 mas ...

for a year before joining the National Science Foundation as a program officer in the Chemistry Division. That was followed by two years at the National Academy of Science in the Division of Earth and Life Sciences. His work there included studies and major reports on air pollution and air quality management. Tolman followed and communicated about climate change issues for over 20 years. He wrote a monthly electronic blog, ''Climate Change News''. He helped write the ''Statement of Conscience on the Threat of Global Warming/Climate Change'' for the

Unitarian Universalist Association Unitarian Universalist Association (UUA) is a liberal religious association of Unitarian Universalist congregations. It was formed in 1961 by the consolidation of the American Unitarian Association and the Universalist Church of America, both P ...

which was adopted by their General Assembly in 2006. Tolman served on a number of advisory committees. He chaired the Energy Committee of the Delaware Chapter of the

Sierra Club The Sierra Club is an environmental organization with chapters in all 50 United States, Washington D.C., and Puerto Rico. The club was founded on May 28, 1892, in San Francisco, California, by Scottish-American preservationist John Muir, who be ...

, and was a member of the Advocacy Committee of the Delaware Nature Society. He was on the Energy Committee of the Delaware

League of Women Voters The League of Women Voters (LWV or the League) is a nonprofit, nonpartisan political organization in the United States. Founded in 1920, its ongoing major activities include registering voters, providing voter information, and advocating for vot ...

, and the Climate Change Task Force of the U.S.

, where he helped write the Toolkit for Climate Change Action He served on the Greenhouse Gas Reduction Advisory Committee and the Sea Level Rise Advisory Committee of the State of

Delaware Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...

. Tolman was presented the Delaware Audubon Conservation Award at the Delaware

Audubon Society The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such organ ...

Annual Meeting on October 9, 2009. Tolman died in Maris Grove, Pennsylvania, on April 6, 2024, at the age of 85.

References

{{DEFAULTSORT:Tolman, Chadwick A. 1938 births 2024 deaths 20th-century American chemists 21st-century American chemists Scientists from Salt Lake City Massachusetts Institute of Technology School of Science alumni DuPont people