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Chadwick A. Tolman
Chadwick Alma Tolman (October 1938 – April 6, 2024) was an American chemist. He obtained his B.S. in Chemistry from Massachusetts Institute of Technology. He earned his Ph.D. in Chemistry as a microwave spectroscopist from U.C. Berkeley under the guidance of William Dulaney Gwinn. Biography Tolman joined DuPont Central Research in 1965. His early work was on late transition metal complexes with phosphorus ligands. The Tolman cone angle and Tolman electronic parameter are named after him. In 1972, he proposed the 16 and 18 electron rule, extending Irving Langmuir'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 for the production of adipic acid, an intermediate in the manufacture of nylon. Tolman was instrumental in the founding of the Delaware Science Alliance and took a year's leave of absence from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Lake City
Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the Capital (political), capital and List of cities and towns in Utah, most populous city of Utah, United States. It is the county seat, seat of Salt Lake County, Utah, Salt Lake County, the most populous county in Utah. With a population of 200,133 in 2020, the city is the core of the Salt Lake City metropolitan area, which had a population of 1,257,936 at the 2020 census. Salt Lake City is further situated within a larger metropolis known as the Salt Lake City–Provo–Orem Combined Statistical Area, Salt Lake City–Ogden–Provo Combined Statistical Area, a corridor of contiguous urban and suburban development stretched along a segment of the Wasatch Front, comprising a population of 2,746,164 (as of 2021 estimates), making it the 22nd largest in the nation. It is also the central core of the larger of only two major urban areas located within the Great Basin (the other being Reno, Nevada). Salt Lake C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16 And 18 Electron Rule
Tolman's rule states that, in a certain chemical reaction, the steps involve exclusively intermediates of 18- and 16 electron configuration. The rule is an extension of the 18-electron rule. This rule was proposed by American chemist Chadwick A. Tolman. As stated above, Tolman's rule, even for reactions that proceed via 2e− steps, is incorrect because many reactions involve configurations of fewer than 16 e−. Many examples of homogeneous catalysis involving organometallic complexes involve shuttling of complexes between 16 and 18 electron configurations. 16-electron complexes often form adducts with Lewis bases and, if low-valent, undergo oxidative addition. : Conversely, complexes of 18 electron configuration tend to dissociate ligands or undergo reductive elimination: : See also * Electron counting Electron counting is a formalism used for classifying compounds and for explaining or predicting electronic structure and bonding. Many rules in chemistry rely on electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2024 Deaths
The following notable deaths occurred in 2024. Names are reported under the date of death, in alphabetical order. A typical entry reports information in the following sequence: * Name, age, country of citizenship at birth, subsequent nationality (if applicable), what subject was noted for, cause of death (if known), and reference. January 26 25 * Hari Shankar Bhabhra, 95, Indian politician, MP (1978–1984), speaker of the Rajasthan Legislative Assembly (1990–1994) and deputy chief minister of Rajasthan (1994–1998). *Bhavatharini, 47, Indian composer ('' Bharathi'', ''Azhagai Irukkirai Bayamai Irukkirathu'') and music director ('' Mitr, My Friend''), cancer. *Roger Donlon, 89, American military officer, Medal of Honor recipient. * Sanath Nishantha, 48, Sri Lankan politician, minister of state for water supply (2020–2022, since 2022) and MP (since 2015), traffic collision. *Elahi Bux Soomro, 97, Pakistani politician, member (1985–2007) and speaker (1996–2001) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1938 Births
Events January * January 1 ** The Constitution of Estonia#Third Constitution (de facto 1938–1940, de jure 1938–1992), new constitution of Estonia enters into force, which many consider to be the ending of the Era of Silence and the authoritarian regime. ** state-owned enterprise, State-owned railway networks are created by merger, in France (SNCF) and the Netherlands (Nederlandse Spoorwegen – NS). * January 20 – King Farouk of Egypt marries Safinaz Zulficar, who becomes Farida of Egypt, Queen Farida, in Cairo. * January 27 – The Honeymoon Bridge (Niagara Falls), Honeymoon Bridge at Niagara Falls, New York, collapses as a result of an ice jam. February * February 4 ** Adolf Hitler abolishes the War Ministry and creates the Oberkommando der Wehrmacht (High Command of the Armed Forces), giving him direct control of the German military. In addition, he dismisses political and military leaders considered unsympathetic to his philosophy or policies. Gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 organizations in the world. There are completely independent Audubon Societies in the United States, which were founded several years earlier such as the Massachusetts Audubon Society and Connecticut Audubon Society. The society has nearly 500 local chapters, each of which is an independent 501(c)(3) non-profit organization voluntarily affiliated with the National Audubon Society. They often organize birdwatching field trips and conservation-related activities. It also coordinates the Christmas Bird Count held each December in the U.S., a model of citizen science, in partnership with Cornell Lab of Ornithology, and the Great Backyard Bird Count each February. Together with Cornell, Audubon created eBird, an online database for bird observati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Delaware Bay, in turn named after Thomas West, 3rd Baron De La Warr, an English nobleman and Virginia's first colonial governor. Delaware occupies the northeastern portion of the Delmarva Peninsula and some islands and territory within the Delaware River. It is the second-smallest and sixth-least populous state, but also the sixth-most densely populated. Delaware's largest city is Wilmington, while the state capital is Dover, the second-largest city in the state. The state is divided into three counties, having the lowest number of counties of any state; from north to south, they are New Castle County, Kent County, and Sussex County. While the southern two counties have historically been predominantly agricultural, New Castle is more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 voting rights. In addition, the LWV works with partners that share its positions and supports a variety of progressive public policy positions, including campaign finance reform, health care reform, and gun control. The League was founded as the successor to the National American Woman Suffrage Association, which had led the nationwide fight for women's suffrage. The initial goals of the League were to educate women to take part in the political process and to push forward legislation of interest to women. As a nonpartisan organization, an important part of its role in American politics has been to register and inform voters, but it also lobbies for issues of importance to its members, which are selected at its biennial conventions. Its ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delaware Nature Society
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 Delaware Bay, in turn named after Thomas West, 3rd Baron De La Warr, an English nobleman and Virginia's first colonial governor. Delaware occupies the northeastern portion of the Delmarva Peninsula and some islands and territory within the Delaware River. It is the second-smallest and sixth-least populous state, but also the sixth-most densely populated. Delaware's largest city is Wilmington, while the state capital is Dover, the second-largest city in the state. The state is divided into three counties, having the lowest number of counties of any state; from north to south, they are New Castle County, Kent County, and Sussex County. While the southern two counties have historically been predominantly agricultural, New Castle is more ur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 became the first president as well as the longest-serving president, at approximately 20 years in this leadership position. The Sierra Club operates only in the United States and holds the legal status of 501(c)(4) nonprofit social welfare organization. Sierra Club Canada is a separate entity. Traditionally associated with the progressive movement, the club was one of the first large-scale environmental preservation organizations in the world, and currently engages in lobbying politicians to promote environmentalist policies. Recent focuses of the club include promoting sustainable energy and mitigating global warming, as well as opposition to the use of coal, hydropower and nuclear power. The club is known for its political endorsements, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Protestant Christian denominations with Unitarian and Universalist doctrines, respectively. However, modern Unitarian Universalists see themselves as a separate religion with its own beliefs and affinities. They define themselves as non- creedal, and draw wisdom from various religions and philosophies, including humanism, pantheism, Christianity, Hinduism, Buddhism, Taoism, Judaism, Islam, and Earth-centered spirituality. Thus, the UUA is a syncretistic religious group with liberal leanings. In the United States, Unitarian Universalism grew by 15.8% between 2000 and 2010 to include 211,000 adherents nationwide. Congregations Most of the member congregations of the UUA are in the United States and Canada, but the UUA has also admitted c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 petroleum, that can be melt-processed into fibers, films, or shapes. Nylon polymers can be mixed with a wide variety of additives to achieve many property variations. Nylon polymers have found significant commercial applications in fabric and fibers (apparel, flooring and rubber reinforcement), in shapes (molded parts for cars, electrical equipment, etc.), and in films (mostly for food packaging). History DuPont and the invention of nylon Researchers at DuPont began developing cellulose based fibers, culminating in the synthetic fiber rayon. DuPont's experience with rayon was an important precursor to its development and marketing of nylon. DuPont's invention of nylon spanned an eleven-year period, ranging from the initial research pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, mainly as a precursor for the production of nylon. Adipic acid otherwise rarely occurs in nature, but it is known as manufactured E number food additive E355. Preparation and reactivity Adipic acid is produced from a mixture of cyclohexanone and cyclohexanol called KA oil, the abbreviation of ketone-alcohol oil. The KA oil is oxidized with nitric acid to give adipic acid, via a multistep pathway. Early in the reaction, the cyclohexanol is converted to the ketone, releasing nitrous acid: :HOC6H11 + HNO3 → OC(CH2)5 + HNO2 + H2O Among its many reactions, the cyclohexanone is nitrosated, setting the stage for the scission of the C-C bond: :HNO2 + HNO3 → NO+NO3− + H2O :OC6H10 + NO+ → OC6H9-2-NO + H+ Side products of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
