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90-574: Below are images of some of the major chasmata of Mars. The map shows their relative locations. Parts of the floor of Candor Chasma contains layered deposits that have been termed interior layered deposits (ILD's). These layers may have formed when the whole area was a giant lake. Some places on Mars contain hydrated sulfate deposits. Sulfate formation involves the presence of water. The European Space Agency 's Mars Express found evidence of perhaps epsomite and kieserite . Scientists want to visit these areas with robotic rovers. Images of rocks in

180-775: A "limited passport" to attend the conference. His full passport was restored in 1954, shortly before the ceremony in Stockholm where he received his first Nobel Prize. Joining Einstein, Bertrand Russell and eight other leading scientists and intellectuals, he signed the Russell-Einstein Manifesto issued July 9, 1955. He also supported the Mainau Declaration of July 15, 1955, signed by 52 Nobel Prize laureates. In May 1957, working with Washington University in St. Louis professor Barry Commoner , Pauling began to circulate

270-507: A Molecular Disease " in the journal Science . It was the first proof of a human disease being caused by an abnormal protein, and sickle cell anemia became the first disease understood at the molecular level. (It was not, however, the first demonstration that variant forms of hemoglobin could be distinguished by electrophoresis, which had been shown several years earlier by Maud Menten and collaborators). Using electrophoresis , they demonstrated that individuals with sickle cell disease have

360-497: A correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. Pauling described this situation as "the biggest disappointment in his life". During the time Pauling was researching the problem, Rosalind Franklin in England

450-637: A degree in chemical engineering . He went on to graduate school at the California Institute of Technology (Caltech) in Pasadena, California , under the guidance of Roscoe Dickinson and Richard Tolman . His graduate research involved the use of X-ray diffraction to determine the structure of crystals . He published seven papers on the crystal structure of minerals while he was at Caltech. He received his PhD in physical chemistry and mathematical physics , summa cum laude , in 1925. In 1926, Pauling

540-450: A direction not always popular with established Caltech chemists. In 1951, Pauling gave a lecture entitled "Molecular Medicine". In the late 1950s, he studied the role of enzymes in brain function, believing that mental illness may be partly caused by enzyme dysfunction. In the 1960s, as part of his interest in the effects of nuclear weapons, he investigated the role of mutations in evolution, proposing with his student Emile Zuckerkandl,

630-570: A ligand attaching either by one oxygen (monodentate) or by two oxygens as either a chelate or a bridge. An example is the complex Co ( en ) 2 (SO 4 )] Br or the neutral metal complex Pt SO 4 ( PPh 3 ) 2 ] where the sulfate ion is acting as a bidentate ligand. The metal–oxygen bonds in sulfate complexes can have significant covalent character. Sulfates are widely used industrially. Major compounds include: Sulfate-reducing bacteria , some anaerobic microorganisms, such as those living in sediment or near deep sea thermal vents, use

720-428: A longitudinal study to measure radioactive strontium -90 in the baby teeth of children across North America. The " Baby Tooth Survey ", published by Louise Reiss , demonstrated conclusively in 1961 that above-ground nuclear testing posed significant public health risks in the form of radioactive fallout spread primarily via milk from cows that had ingested contaminated grass. The Committee for Nuclear Information

810-400: A modified form of hemoglobin in their red blood cells , and that individuals with sickle cell trait have both the normal and abnormal forms of hemoglobin. This was the first demonstration causally linking an abnormal protein to a disease, and also the first demonstration that Mendelian inheritance determines the specific physical properties of proteins, not simply their presence or absence –

900-404: A month (equivalent to US$ 1,500 in 2023), enabling him to continue his studies. In his last two years at school, Pauling became aware of the work of Gilbert N. Lewis and Irving Langmuir on the electronic structure of atoms and their bonding to form molecules . He decided to focus his research on how the physical and chemical properties of substances are related to the structure of

990-416: A petition among scientists to stop nuclear testing. On January 15, 1958, Pauling and his wife presented a petition to United Nations Secretary General Dag Hammarskjöld calling for an end to the testing of nuclear weapons . It was signed by 11,021 scientists representing fifty countries. In February 1958, Pauling participated in a publicly televised debate with the atomic physicist Edward Teller about

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1080-444: A pioneer in the application of quantum theory to the structure of molecules. In 1927, Pauling took a new position as an assistant professor at Caltech in theoretical chemistry . He launched his faculty career with a very productive five years, continuing with his X-ray crystal studies and also performing quantum mechanical calculations on atoms and molecules. He published approximately fifty papers in those five years, and created

1170-566: A possible replacement for human blood plasma in transfusions : polyoxy gelatin (Oxypolygelatin). Other wartime projects with more direct military applications included work on explosives, rocket propellants and the patent for an armor-piercing shell. In October 1948, Pauling, along with Lee A. DuBridge , William A. Fowler , Max Mason , and Bruce H. Sage , was awarded a Presidential Medal for Merit by President Harry S. Truman . The citation credits him for his "imaginative mind", "brilliant success", and "exceptionally meritorious conduct in

1260-662: A salt containing the HSO − 4 ion is sodium bisulfate , NaHSO 4 . In dilute solutions the hydrogensulfate ions also dissociate, forming more hydronium ions and sulfate ions ( SO 2− 4 ). Linus Pauling Post-docs: Linus Carl Pauling FRS ( / ˈ p ɔː l ɪ ŋ / PAW -ling ; February 28, 1901 – August 19, 1994) was an American chemist , biochemist , chemical engineer , peace activist , author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of

1350-419: A stunning personal collection of minerals. The two men planned to mount a joint attack on the nature of the chemical bond: apparently Oppenheimer would supply the mathematics and Pauling would interpret the results. Their relationship soured when Oppenheimer tried to pursue Pauling's wife, Ava Helen. When Pauling was at work, Oppenheimer came to their home and blurted out an invitation to Ava Helen to join him on

1440-533: A tryst in Mexico. She flatly refused, and reported the incident to Pauling. He immediately cut off his relationship with Oppenheimer. In the summer of 1930, Pauling made another European trip, during which he learned about gas-phase electron diffraction from Herman Francis Mark . After returning, he built an electron diffraction instrument at Caltech with a student of his, Lawrence Olin Brockway , and used it to study

1530-414: A way that the protein molecules were tilted from their expected positions. Pauling had formulated a model for the structure of hemoglobin in which atoms were arranged in a helical pattern, and applied this idea to proteins in general. In 1951, based on the structures of amino acids and peptides and the planar nature of the peptide bond , Pauling, Robert Corey and Herman Branson correctly proposed

1620-487: Is a relatively short-lived greenhouse gas), it is believed that simultaneous reductions in both would effectively cancel each other out. On regional and global scale, air pollution can affect the water cycle , in a manner similar to some natural processes. One example is the impact of Sahara dust on hurricane formation: air laden with sand and mineral particles moves over the Atlantic Ocean, where they block some of

1710-461: Is common on Mars. However, light-toned deposits may have resulted from rivers, lakes, volcanic ash, or wind blown deposits of sand or dust. The Mars Rovers found light-toned rocks to contain sulfates . Probably having been formed in water, sulfate deposits are of great interest to scientists because they may contain traces of ancient life. Hebes Chasma, a large enclosed valley, may have once held water. Hydrated minerals have been found there. It

1800-514: Is frequently credited for its significant contribution to supporting the test ban, as is the ground-breaking research conducted by Reiss and the "Baby Tooth Survey". Public pressure and the frightening results of the CNI research led to a moratorium on above-ground nuclear weapons testing, followed by the Partial Test Ban Treaty , signed in 1963 by John F. Kennedy and Nikita Khrushchev . On

1890-588: Is shown below in the picture of layers in the canyon wall in Coprates, as seen by Mars Global Surveyor . Because of its closeness to the Tharsis volcanic region, the rock layers may be made of layer after layer of lava flows, probably mixed with deposits of volcanic ash that fell out of the air following big eruptions. It is likely the rock strata in the walls preserve a long geological history of Mars. Dark layers may be due to dark lava flows. The dark volcanic rock basalt

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1980-408: Is the conjugate base of sulfuric acid ( H 2 SO 4 ). Sulfuric acid is classified as a strong acid; in aqueous solutions it ionizes completely to form hydronium ( H 3 O ) and hydrogensulfate ( HSO − 4 ) ions. In other words, the sulfuric acid behaves as a Brønsted–Lowry acid and is deprotonated to form hydrogensulfate ion. Hydrogensulfate has a valency of 1. An example of

2070-417: Is the conjugate base of the bisulfate (or hydrogensulfate) ion, HSO − 4 , which is in turn the conjugate base of H 2 SO 4 , sulfuric acid . Organic sulfate esters , such as dimethyl sulfate , are covalent compounds and esters of sulfuric acid. The tetrahedral molecular geometry of the sulfate ion is as predicted by VSEPR theory . The first description of the bonding in modern terms

2160-401: Is the most insoluble sulfate known. The barium derivative is useful in the gravimetric analysis of sulfate: if one adds a solution of most barium salts, for instance barium chloride , to a solution containing sulfate ions, barium sulfate will precipitate out of solution as a whitish powder. This is a common laboratory test to determine if sulfate anions are present. The sulfate ion can act as

2250-514: Is the spelling recommended by IUPAC , but "sulphate" was traditionally used in British English . The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The symmetry of the isolated anion is the same as that of methane. The sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries an overall charge of −2 and it

2340-599: Is thought that large-scale underground springs of groundwater at different times burst to the surface to form deposits called Light Toned Deposits (LTD's). Some suggest present or fossilized life forms may be found there because the deposits are relatively young. Sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula SO 2− 4 . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid. "Sulfate"

2430-593: Is useful in predicting the nature of bonds between atoms in molecules. In 1936, Pauling was promoted to chairman of the division of chemistry and chemical engineering at Caltech, and to the position of director of the Gates and Crellin Laboratories of Chemistry. He would hold both positions until 1958. Pauling also spent a year in 1948 at the University of Oxford as George Eastman Visiting Professor and Fellow of Balliol. In

2520-518: Is zinc sulfate heptahydrate, ZnSO 4 ·7H 2 O . Alum , a double sulfate of potassium and aluminium with the formula K 2 Al 2 (SO 4 ) 4 ·24H 2 O , figured in the development of the chemical industry. Sulfates occur as microscopic particles ( aerosols ) resulting from fossil fuel and biomass combustion. They increase the acidity of the atmosphere and form acid rain . The anaerobic sulfate-reducing bacteria Desulfovibrio desulfuricans and D. vulgaris can remove

2610-653: The Proceedings of the National Academy of Sciences . For nearly three decades, until his death in 1994, Pauling published numerous papers on his spheron cluster model. The basic idea behind Pauling's spheron model is that a nucleus can be viewed as a set of "clusters of nucleons". The basic nucleon clusters include the deuteron [np], helion [pnp], and triton [npn]. Even–even nuclei are described as being composed of clusters of alpha particles , as has often been done for light nuclei. Pauling attempted to derive

2700-582: The Independent Citizens Committee of the Arts, Sciences and Professions (ICCASP) on atomic weapons ; shortly after, wife Ava and he accepted membership. On January 21, 1946, the group met to discuss academic freedom , during which Pauling said, "There is, of course, always a threat to academic freedom – as there is to the other aspects of the freedom and rights of the individual, in the continued attacks which are made on this freedom, these rights, by

2790-621: The Nobel Prize in Chemistry in 1954 "for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances". Pauling's book has been considered "chemistry's most influential book of this century and its effective bible". In the 30 years after its first edition was published in 1939, the book was cited more than 16,000 times. Even today, many modern scientific papers and articles in important journals cite this work, more than seventy years after

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2880-438: The alpha helix and beta sheet as the primary structural motifs in protein secondary structure . This work exemplified Pauling's ability to think unconventionally; central to the structure was the unorthodox assumption that one turn of the helix may well contain a non- integer number of amino acid residues; for the alpha helix it is 3.7 amino acid residues per turn. Pauling then proposed that deoxyribonucleic acid (DNA)

2970-416: The electronic structure of atoms and molecules. In Zürich, Pauling was also exposed to one of the first quantum mechanical analyses of bonding in the hydrogen molecule, done by Walter Heitler and Fritz London . Pauling devoted the two years of his European trip to this work and decided to make it the focus of his future research. He became one of the first scientists in the field of quantum chemistry and

3060-492: The molecular structure of a large number of chemical substances. Pauling introduced the concept of electronegativity in 1932. Using the various properties of molecules, such as the energy required to break bonds and the dipole moments of molecules, he established a scale and an associated numerical value for most of the elements  —  the Pauling Electronegativity Scale  —  which

3150-424: The quantum-mechanical wave function for a polar molecule AB is a combination of wave functions for covalent and ionic molecules. Here Pauling's electronegativity concept is particularly useful; the electronegativity difference between a pair of atoms will be the surest predictor of the degree of ionicity of the bond. The third of the topics that Pauling attacked under the overall heading of "the nature of

3240-571: The 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize (the others being Marie Curie , John Bardeen , Frederick Sanger , and Karl Barry Sharpless ). Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields,

3330-473: The Chemistry division of the project. He declined, not wanting to uproot his family. Pauling did, however, work on research for the military. He was a principal investigator on 14 OSRD contracts . The National Defense Research Committee called a meeting on October 3, 1940, wanting an instrument that could reliably measure oxygen content in a mixture of gases, so that they could measure oxygen conditions in submarines and airplanes. In response Pauling designed

3420-597: The Pauling oxygen meter, which was developed and manufactured by Arnold O. Beckman, Inc. After the war, Beckman adapted the oxygen analyzers for use in incubators for premature babies. In 1942, Pauling successfully submitted a proposal on "The Chemical Treatment of Protein Solutions in the Attempt to Find a Substitute for Human Serum for Transfusions". His project group, which included Joseph B. Koepfli and Dan H. Campbell, developed

3510-556: The Reduction of Sulfur Emissions under the Convention on Long-Range Transboundary Air Pollution , and with similar improvements. Since changes in aerosol concentrations already have an impact on the global climate, they would necessarily influence future projections as well. In fact, it is impossible to fully estimate the warming impact of all greenhouse gases without accounting for the counteracting cooling from aerosols. Regardless of

3600-504: The S−O bonds, the bond has significant ionic character. For sulfuric acid, computational analysis (with natural bond orbitals ) confirms a clear positive charge on sulfur (theoretically +2.45) and a low 3d occupancy. Therefore, the representation with four single bonds is the optimal Lewis structure rather than the one with two double bonds (thus the Lewis model, not the Pauling model). In this model,

3690-608: The actual probability of fallout causing mutations. Later in 1958, Pauling published No more war! , in which he not only called for an end to the testing of nuclear weapons but also an end to war itself. He proposed that a World Peace Research Organization be set up as part of the United Nations to "attack the problem of preserving the peace". Pauling also supported the work of the St. Louis Citizen's Committee for Nuclear Information (CNI). This group, headed by Barry Commoner , Eric Reiss, M. W. Friedlander and John Fowler, organized

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3780-468: The appropriate orbitals to describe certain unsaturated carbon compounds such as ethylene . Other hybridization schemes are also found in other types of molecules. Another area which he explored was the relationship between ionic bonding , where electrons are transferred between atoms, and covalent bonding , where electrons are shared between atoms on an equal basis. Pauling showed that these were merely extremes, and that for most actual cases of bonding,

3870-471: The atoms of which they are composed, becoming one of the founders of the new science of quantum chemistry. Engineering professor Samuel Graf (1887–1966) selected Pauling to be his teaching assistant in a mechanics and materials course. During the winter of his senior year, Pauling taught a chemistry course for home economics majors. It was in one of these classes that Pauling met his future wife, Ava Helen Miller . In 1922, Pauling graduated with

3960-510: The black sulfate crust that often tarnishes buildings. After 1990, the global dimming trend had clearly switched to global brightening. This followed measures taken to combat air pollution by the developed nations , typically through flue-gas desulfurization installations at thermal power plants , such as wet scrubbers or fluidized bed combustion . In the United States, sulfate aerosols have declined significantly since 1970 with

4050-451: The canyon walls almost always show layers. Some layers appear tougher than others. In the image below of Ganges Chasma Layers, as seen by HiRISE , one can see that the upper, light-toned deposits are eroding much faster than the lower darker layers. Some cliffs on Mars show a few darker layers standing out and often breaking into large pieces; these are thought to be hard volcanic rock instead of soft ash deposits. An example of hard layers

4140-468: The chemical bond" was the accounting of the structure of aromatic hydrocarbons , particularly the prototype, benzene . The best description of benzene had been made by the German chemist Friedrich Kekulé . He had treated it as a rapid interconversion between two structures, each with alternating single and double bonds , but with the double bonds of one structure in the locations where the single bonds were in

4230-489: The concept of hybridization of atomic orbitals and analyzed the tetravalency of the carbon atom. At Caltech, Pauling struck up a close friendship with theoretical physicist Robert Oppenheimer at the University of California, Berkeley , who spent part of his research and teaching schedule as a visitor at Caltech each year. Pauling was also affiliated with Berkeley, serving as a visiting lecturer in physics and chemistry from 1929 to 1934. Oppenheimer even gave Pauling

4320-458: The crystalline minerals of his former work. The best X-ray pictures of proteins in the 1930s had been made by the British crystallographer William Astbury , but when Pauling tried, in 1937, to account for Astbury's observations quantum mechanically, he could not. It took eleven years for Pauling to explain the problem: his mathematical analysis was correct, but Astbury's pictures were taken in such

4410-456: The current strength of aerosol cooling, all future climate change scenarios project decreases in particulates and this includes the scenarios where 1.5 °C (2.7 °F) and 2 °C (3.6 °F) targets are met: their specific emission reduction targets assume the need to make up for lower dimming. Since models estimate that the cooling caused by sulfates is largely equivalent to the warming caused by atmospheric methane (and since methane

4500-743: The dangers associated with the development of nuclear weapons. His political activism prompted the US State Department to deny him a passport in 1952, when he was invited to speak at a scientific conference in London. In a speech before the US Senate on June 6 of the same year, Senator Wayne Morse publicly denounced the action of the State Department, and urged the Passport Division to reverse its decision. Pauling and his wife Ava were then issued

4590-554: The dawn of molecular genetics . His success with sickle cell anemia led Pauling to speculate that a number of other diseases, including mental illnesses such as schizophrenia , might result from flawed genetics. As chairman of the Division of Chemistry and Chemical Engineering and director of the Gates and Crellin Chemical Laboratories, he encouraged the hiring of researchers with a chemical-biomedical approach to mental illness,

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4680-494: The day that the treaty went into force, October 10, 1963, the Nobel Prize Committee awarded Pauling the Nobel Peace Prize for 1962. (No prize had previously been awarded for that year.) They described him as "Linus Carl Pauling, who ever since 1946 has campaigned ceaselessly, not only against nuclear weapons tests, not only against the spread of these armaments, not only against their very use, but against all warfare as

4770-445: The discoveries that he had already found. Pauling also studied enzyme reactions and was among the first to point out that enzymes bring about reactions by stabilizing the transition state of the reaction, a view which is central to understanding their mechanism of action. He was also among the first scientists to postulate that the binding of antibodies to antigens would be due to a complementarity between their structures. Along

4860-417: The first publication. Part of Pauling's work on the nature of the chemical bond led to his introduction of the concept of orbital hybridization . While it is normal to think of the electrons in an atom as being described by orbitals of types such as s and p , it turns out that in describing the bonding in molecules, it is better to construct functions that partake of some of the properties of each. Thus

4950-528: The five rules now known as Pauling's rules . By 1929, he was promoted to associate professor, and by 1930, to full professor. In 1931, the American Chemical Society awarded Pauling the Langmuir Prize for the most significant work in pure science by a person 30 years of age or younger. The following year, Pauling published what he regarded as his most important paper, in which he first laid out

5040-495: The high school senior had enough credits to enter Oregon State University (OSU), known then as Oregon Agricultural College. Lacking two American history courses required for his high school diploma , Pauling asked the school principal if he could take the courses concurrently during the spring semester. Denied, he left Washington High School in June without a diploma. The school awarded him an honorary diploma 45 years later, after he

5130-477: The late 1920s, Pauling began publishing papers on the nature of the chemical bond . Between 1937 and 1938, he took a position as George Fischer Baker Non-Resident Lecturer in Chemistry at Cornell University . While at Cornell, he delivered a series of nineteen lectures and completed the bulk of his famous textbook The Nature of the Chemical Bond . It is based primarily on his work in this area that he received

5220-406: The latter. However, Pauling's representation for sulfate and other main group compounds with oxygen is still a common way of representing the bonding in many textbooks. The apparent contradiction can be clarified if one realizes that the covalent double bonds in the Lewis structure actually represent bonds that are strongly polarized by more than 90% towards the oxygen atom. On the other hand, in

5310-640: The legend that Pauling missed the structure of DNA because of the politics of the day (this was at the start of the McCarthy period in the United States). Politics did not play a critical role. Not only did Corey see the images at the time, but Pauling himself regained his passport within a few weeks and toured English laboratories well before writing his DNA paper. He had ample opportunity to visit Franklin's lab and see her work, but chose not to. Despite these times, Pauling chose to move on from them and be thankful for

5400-654: The medical usefulness of large doses of vitamins have gained much acceptance in the mainstream scientific community. He was married to the American human rights activist Ava Helen Pauling . Linus Carl Pauling was born on February 28, 1901, in Portland, Oregon , the firstborn child of Herman Henry William Pauling (1876–1910) and Lucy Isabelle "Belle" Darling (1881–1926). He was named "Linus Carl", in honor of Lucy's father, Linus, and Herman's father, Carl. His ancestry included German and English. In 1902, after his sister Pauline

5490-404: The molecular evolutionary clock, the idea that mutations in proteins and DNA accumulate at a constant rate over time . On September 16, 1952, Pauling opened a new research notebook with the words "I have decided to attack the problem of the structure of nuclei." On October 15, 1965, Pauling published his Close-Packed Spheron Model of the atomic nucleus in two well respected journals, Science and

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5580-429: The one 2s and three 2p orbitals in a carbon atom can be (mathematically) 'mixed' or combined to make four equivalent orbitals (called sp hybrid orbitals), which would be the appropriate orbitals to describe carbon compounds such as methane , or the 2s orbital may be combined with two of the 2p orbitals to make three equivalent orbitals (called sp hybrid orbitals), with the remaining 2p orbital unhybridized, which would be

5670-614: The other being Marie Curie . Pauling was one of the founders of the fields of quantum chemistry and molecular biology . His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativities of the elements. Pauling also worked on the structures of biological molecules, and showed the importance of the alpha helix and beta sheet in protein secondary structure . Pauling's approach combined methods and results from X-ray crystallography , molecular model building, and quantum chemistry. His discoveries inspired

5760-667: The other. Pauling showed that a proper description based on quantum mechanics was an intermediate structure which was a blend of each. The structure was a superposition of structures rather than a rapid interconversion between them. The name " resonance " was later applied to this phenomenon. In a sense, this phenomenon resembles those of hybridization and also polar bonding, both described above, because all three phenomena involve combining more than one electronic structure to achieve an intermediate result. In 1929, Pauling published five rules which help to predict and explain crystal structures of ionic compounds . These rules concern (1)

5850-615: The passage of the Clean Air Act , which was strengthened in 1977 and 1990. According to the EPA , from 1970 to 2005, total emissions of the six principal air pollutants, including sulfates, dropped by 53% in the US. By 2010, this reduction in sulfate pollution led to estimated healthcare cost savings valued at $ 50 billion annually. Similar measures were taken in Europe, such as the 1985 Helsinki Protocol on

5940-512: The peptide bond. When it was learned at the Cavendish Laboratory that Pauling was working on molecular models of the structure of DNA, James Watson and Francis Crick were allowed to make a molecular model of DNA. They later benefited from unpublished data from Maurice Wilkins and Rosalind Franklin at King's College which showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 Watson and Crick proposed

6030-527: The performance of outstanding services". In 1949, he served as president of the American Chemical Society . The aftermath of the Manhattan Project and his wife Ava's pacifism changed Pauling's life profoundly, and he became a peace activist. In June 1945, a "May-Johnson Bill" began that would become the Atomic Energy Act of 1946 (signed August 1, 1946). In November 1945, Pauling spoke to

6120-471: The physics literature, Physical Review Letters and other journals, I know that many physicists are interested in atomic nuclei, but none of them, so far as I have been able to discover, has been attacking the problem in the same way that I attack it. So I just move along at my own speed, making calculations ... Pauling had been practically apolitical until World War II . At the beginning of the Manhattan Project , Robert Oppenheimer invited him to be in charge of

6210-938: The ratio of cation radius to anion radius, (2) the electrostatic bond strength, (3) the sharing of polyhedron corners, edges and faces, (4) crystals containing different cations, and (5) the rule of parsimony. In the mid-1930s, Pauling, strongly influenced by the biologically oriented funding priorities of the Rockefeller Foundation's Warren Weaver , decided to strike out into new areas of interest. Although Pauling's early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological importance, in part because of Caltech's growing strength in biology. Pauling interacted with such great biologists as Thomas Hunt Morgan , Theodosius Dobzhanski , Calvin Bridges and Alfred Sturtevant . His early work in this area included studies of

6300-531: The reduction of sulfates coupled with the oxidation of organic compounds or hydrogen as an energy source for chemosynthesis. Some sulfates were known to alchemists. The vitriol salts, from the Latin vitreolum , glassy, were so-called because they were some of the first transparent crystals known. Green vitriol is iron (II) sulfate heptahydrate, FeSO 4 ·7H 2 O ; blue vitriol is copper (II) sulfate pentahydrate, CuSO 4 ·5H 2 O and white vitriol

6390-424: The same lines, with the physicist turned biologist Max Delbrück , he wrote an early paper arguing that DNA replication was likely to be due to complementarity , rather than similarity, as suggested by a few researchers. This was made clear in the model of the structure of DNA that Watson and Crick discovered. In November 1949, Pauling, Harvey Itano , S. J. Singer and Ibert Wells published " Sickle Cell Anemia,

6480-469: The selfish, the overly ambitious, the misguided, the unscrupulous, who seek to oppress the great body of mankind in order that they themselves may profit – and we must always be on the alert against this threat, and must fight it with vigor when it becomes dangerous." In 1946, he joined the Emergency Committee of Atomic Scientists , chaired by Albert Einstein . Its mission was to warn the public of

6570-438: The shell structure of nuclei from pure geometrical considerations related to Platonic solids rather than starting from an independent particle model as in the usual shell model . In an interview given in 1990 Pauling commented on his model: Now recently, I have been trying to determine detailed structures of atomic nuclei by analyzing the ground state and excited state vibrational bends, as observed experimentally. From reading

6660-485: The shortening of the S−O bond. The outcome was a broad consensus that d orbitals play a role, but are not as significant as Pauling had believed. A widely accepted description involving pπ – dπ bonding was initially proposed by Durward William John Cruickshank . In this model, fully occupied p orbitals on oxygen overlap with empty sulfur d orbitals (principally the d z and d x – y ). However, in this description, despite there being some π character to

6750-458: The structure obeys the octet rule and the charge distribution is in agreement with the electronegativity of the atoms. The discrepancy between the S−O bond length in the sulfate ion and the S−OH bond length in sulfuric acid is explained by donation of p-orbital electrons from the terminal S=O bonds in sulfuric acid into the antibonding S−OH orbitals, weakening them resulting in the longer bond length of

6840-420: The structure of hemoglobin with his student Charles D. Coryell . He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen molecule. As a result of this observation, he decided to conduct a more thorough study of protein structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than

6930-893: The structure with a dipolar bond , the charge is localized as a lone pair on the oxygen. Typically metal sulfates are prepared by treating metal oxides, metal carbonates, or the metal itself with sulfuric acid : Although written with simple anhydrous formulas, these conversions generally are conducted in the presence of water. Consequently the product sulfates are hydrated , corresponding to zinc sulfate ZnSO 4 ·7H 2 O , copper(II) sulfate CuSO 4 ·5H 2 O , and cadmium sulfate CdSO 4 ·H 2 O . Some metal sulfides can be oxidized to give metal sulfates. There are numerous examples of ionic sulfates, many of which are highly soluble in water . Exceptions include calcium sulfate , strontium sulfate , lead(II) sulfate , barium sulfate , silver sulfate , and mercury sulfate , which are poorly soluble. Radium sulfate

7020-418: The sunlight from reaching the water surface, slightly cooling it and dampening the development of hurricanes. Likewise, it has been suggested since the early 2000s that since aerosols decrease solar radiation over the ocean and hence reduce evaporation from it, they would be "spinning down the hydrological cycle of the planet." The hydrogensulfate ion ( HSO − 4 ), also called the bisulfate ion,

7110-479: The work of Rosalind Franklin , James Watson , Francis Crick , and Maurice Wilkins on the structure of DNA , which in turn made it possible for geneticists to crack the DNA code of all organisms. In his later years, he promoted nuclear disarmament , as well as orthomolecular medicine , megavitamin therapy , and dietary supplements , especially ascorbic acid (commonly known as Vitamin C). None of his ideas concerning

7200-473: The world." In high school, Pauling conducted chemistry experiments by scavenging equipment and material from an abandoned steel plant. With an older friend, Lloyd Simon, Pauling set up Palmon Laboratories in Simon's basement. They approached local dairies offering to perform butterfat samplings at cheap prices but dairymen were wary of trusting two boys with the task, and the business ended in failure. At age 15,

7290-404: Was a triple helix ; his model contained several basic mistakes, including a proposal of neutral phosphate groups, an idea that conflicted with the acidity of DNA. Sir Lawrence Bragg had been disappointed that Pauling had won the race to find the alpha helix structure of proteins. Bragg's team had made a fundamental error in making their models of protein by not recognizing the planar nature of

7380-621: Was awarded a Guggenheim Fellowship to travel to Europe, to study under German physicist Arnold Sommerfeld in Munich, Danish physicist Niels Bohr in Copenhagen and Austrian physicist Erwin Schrödinger in Zürich . All three were experts in the new field of quantum mechanics and other branches of physics. Pauling became interested in how quantum mechanics might be applied in his chosen field of interest,

7470-495: Was awarded two Nobel Prizes. Pauling held a number of jobs to earn money for his future college expenses, including working part-time at a grocery store for US$ 8 per week (equivalent to US$ 220 in 2023). His mother arranged an interview with the owner of a number of manufacturing plants in Portland, Mr. Schwietzerhoff, who hired him as an apprentice machinist at a salary of US$ 40 per month (equivalent to US$ 1,120 in 2023). This

7560-636: Was born, Pauling's parents decided to move out of Portland to find more affordable and spacious living quarters than their one-room apartment. Lucy stayed with her husband's parents in Oswego until Herman brought the family to Salem , where he worked briefly as a traveling salesman for the Skidmore Drug Company. Within a year of Lucile's birth in 1904, Herman Pauling moved his family to Oswego, Oregon where he opened his own drugstore. He moved his family to Condon, Oregon , in 1905. By 1906, Herman Pauling

7650-403: Was by Gilbert Lewis in his groundbreaking paper of 1916 where he described the bonding in terms of electron octets around each atom, that is no double bonds and a formal charge of +2 on the sulfur atom and -1 on each oxygen atom. Later, Linus Pauling used valence bond theory to propose that the most significant resonance canonicals had two pi bonds involving d orbitals. His reasoning

7740-497: Was childhood pal and lifelong best friend Lloyd Jeffress. He was active in campus life and founded the school's chapter of the Delta Upsilon fraternity. After his second year, he planned to take a job in Portland to help support his mother. The college offered him a position teaching quantitative analysis , a course he had just finished taking himself. He worked forty hours a week in the laboratory and classroom and earned US$ 100

7830-456: Was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert Corey did see at least some of them, while taking Pauling's place at a summer 1952 protein conference in England. Pauling had been prevented from attending because his passport was withheld by the State Department on suspicion that he had Communist sympathies. This led to

7920-542: Was soon raised to US$ 50 per month. Pauling also set up a photography laboratory with two friends. In September 1917, Pauling was finally admitted by Oregon State University. He immediately resigned from the machinist's job and informed his mother, who saw no point in a university education, of his plans. In his first semester, Pauling registered for two courses in chemistry, two in mathematics, mechanical drawing, introduction to mining and use of explosives, modern English prose, gymnastics and military drill. His roommate

8010-527: Was suffering from recurrent abdominal pain . He died of a perforated ulcer on June 11, 1910, leaving Lucy to care for Linus, Lucile and Pauline. Pauling attributes his interest in becoming a chemist to being amazed by experiments conducted by a friend, Lloyd A. Jeffress , who had a small chemistry lab kit. He later wrote: "I was simply entranced by chemical phenomena, by the reactions in which substances, often with strikingly different properties, appear; and I hoped to learn more and more about this aspect of

8100-452: Was that the charge on sulfur was thus reduced, in accordance with his principle of electroneutrality . The S−O bond length of 149 pm is shorter than the bond lengths in sulfuric acid of 157 pm for S−OH. The double bonding was taken by Pauling to account for the shortness of the S−O bond. Pauling's use of d orbitals provoked a debate on the relative importance of pi bonding and bond polarity ( electrostatic attraction ) in causing

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