History of chemistry 1416046 226077853 2008-07-16T18:56:41Z ClueBot 4928500 Reverting possible vandalism by [[Special:Contributions/82.22.150.52|82.22.150.52]] to version by Jagged 85. False positive? [[User:ClueBot/FalsePositives|Report it]]. Thanks, [[User:ClueBot]]. (441727) (Bot) {{Refimprove|date=July 2008}} {{History of science}} The '''history of [[chemistry]]''' begins with the discovery of [[fire]], then [[metallurgy]] which allowed purification of metals and the making of alloys, as well as the exploitation of many minerals and natural substances. The protoscience of [[alchemy]] attempted to explain the nature of matter and its transformations. This was followed by the development of a [[scientific method]] by [[Geber]], and then refutations of alchemy and the [[classical element]]s by several [[Alchemy and chemistry in Islam|Arabic chemists]]. Modern chemistry begins to emerge when a clear distinction is made between chemistry and alchemy by [[Robert Boyle]] in his work ''[[The Sceptical Chymist]]'' (1661). Chemistry then becomes a full-fledged science when [[Antoine Lavoisier]] develops his law of [[conservation of mass]], which demands careful measurements and quantitative observations of chemical phenomena. So, while both alchemy and chemistry are concerned with the nature of matter and its transformations, it is only the [[chemist]]s who apply the [[scientific method]].The history of chemistry is intertwined with the [[history of thermodynamics]], especially through the work of [[Willard Gibbs]]. ===From fire to atomism=== Arguably the first chemical reaction that was used in a controlled manner by mankind was [[combustion|fire]]. However, for millennia, in absence of a scientific understanding, [[fire]] was simply a mystical force that could transform one substance into another (burn the wood, or boil the water) while producing heat and light. Fire affected many aspects of early societies, ranging from the most simple facets of everyday life, such as cooking and habitat lighting, to more advanced technologies, such as pottery, bricks, and smelting of metals to make tools. [[philosophy|Philosophical]] attempts to rationalize why different substances have different properties (color, density, smell), exist in different states (gaseous, liquid, and solid), and react in a different manner when exposed to environments, for example to water or fire or temperature changes, led ancient philosophers to postulate the first theories on nature and chemistry. The history of such philosophical theories that relate to chemistry, can probably be traced back to every single ancient civilization. The common aspect in all these theories was the attempt to identify a small number of primary [[Classical element|elements]] that make up all the various substances in nature. Substances like air, water, and soil/earth, energy forms, such as fire and light, and more abstract concepts such as ideas, aether, and heaven, were common in ancient civilizations even in absence of any cross-fertilization; for example in Greek, Indian, Mayan, and ancient Chinese philosophies all considered air, water, earth and fire as [[Classical element|primary elements]].{{Fact|date=June 2008}} [[Atomism]] can be traced back to [[ancient Greece]] and [[ancient India]].{{Fact|date=August 2007}} Greek atomism dates back to 440 BC, as what might be indicated by the book ''De Rerum Natura'' (The Nature of Things)<ref>{{ cite web | last = Lucretius | title = de Rerum Natura (On the Nature of Things) | work = The Internet Classics Archive | publisher = Massachusetts Institute of Technology | date = 50 BCE | url = http://classics.mit.edu/Carus/nature_things.html | accessdate = 2007-01-09}} </ref> written by the Roman [[Lucretius]]<ref>{{ cite web | last = Simpson | first = David | title = Lucretius (c. 99 - c. 55 BCE) | work = The Internet History of Philosophy | date = [[29 June]] [[2005]] | url = http://www.iep.utm.edu/l/lucretiu.htm | accessdate = 2007-01-09}} </ref> in 50 BC. In the book was found ideas traced back to [[Democritus]] and [[Leucippus]], who declared that atoms were the most indivisible part of matter. This coincided with a similar declaration by [[Indian philosophy|Indian]] philosopher [[Kanada]] in his [[Vaisheshika]] [[sutra]]s around the same time period.<ref> [[Will Durant]] (1935), ''Our Oriental Heritage'': <br>{{quote|"Two systems of [[Hindu]] thought propound [[physics|physical]] theories suggestively similar to those of [[Ancient Greece|Greece]]. [[Kanada]], founder of the [[Vaisheshika]] philosophy, held that the world was composed of atoms as many in kind as the various elements. The [[Jainism|Jains]] more nearly approximated to [[Democritus]] by teaching that all atoms were of the same kind, producing different effects by diverse modes of combinations. Kanada believed [[light]] and [[heat]] to be varieties of the same substance; [[Udayana]] taught that all heat comes from the sun; and [[Vācaspati Miśra|Vachaspati]], like [[Isaac Newton|Newton]], interpreted light as composed of minute particles emitted by substances and striking the eye."}} </ref> Kashyapa may have arrived at his sutras by [[meditation]]. By similar means discussed the existence of [[gas]]es. What Kanada declared by sutra, Democritus declared by philosophical musing. Both suffered from a lack of [[empiricism|empirical]] data. Without scientific proof, the existence of atoms was easy to deny. [[Aristotle]] opposed the existence of atoms in 330 BC; and the atomism of the Vaisheshika school was also opposed for a long time.{{Fact|date=August 2007}} Much of the early development of purification methods is described by [[Pliny the Elder]] in his [[Naturalis Historia]]. He made attempts to explain those methods, as well as making acute observations of the state of many minerals. ===The rise of metallurgy=== {{main|History of ferrous metallurgy}} It was fire that led to the discovery of [[glass]] and the [[purification]] of [[metal]]s which in turn gave way to the rise of [[metallurgy]].{{Fact|date=August 2007}} During the early stages of metallurgy, methods of purification of metals were sought, and [[gold]], known in [[ancient Egypt]] as early as 2600 BCE, became a precious metal. The discovery of [[alloy]]s heralded the [[Bronze Age]]. After the Bronze Age, the history of metallurgy was marked by which army had better weaponry. Countries in [[Eurasia]] had their heyday when they made the superior alloys, which, in turn, made better armour and better weapons. This often determined the outcomes of battles.{{Fact|date=August 2007}} ====Indian metallurgy and alchemy==== {{main|History of metallurgy in the Indian subcontinent}} Significant progress in metallurgy and alchemy was made in [[ancient India]]. [[Will Durant]] wrote in ''[[The Story of Civilization]] I: Our Oriental Heritage'': {{quote|"Something has been said about the chemical excellence of [[cast iron]] in ancient India, and about the high industrial development of the [[Gupta Empire|Gupta]] times, when India was looked to, even by [[Roman Empire|Imperial Rome]], as the most skilled of the nations in such chemical [[industry|industries]] as [[dye]]ing, [[tanning]], [[soap]]-making, [[glass]] and [[cement]]... By the sixth century the [[Hindu]]s were far ahead of Europe in industrial chemistry; they were masters of [[calcination]]s, [[distillation]], [[Sublimation (chemistry)|sublimation]], [[steaming]], [[Fixation (alchemy)|fixation]], the production of [[light]] without [[heat]], the mixing of [[Anesthesia|anesthetic]] and [[Sleep|soporific]] powders, and the preparation of [[metal]]lic [[salt]]s, [[Chemical compound|compounds]] and [[alloy]]s. The tempering of steel was brought in ancient India to a perfection unknown in Europe till our own times; King [[Porus]] is said to have selected, as a specially valuable gift from [[Alexander the Great|Alexander]], not gold or silver, but thirty pounds of steel. The Moslems took much of this Hindu chemical science and industry to the [[Near East]] and [[Europe]]; the secret of manufacturing [[Damascus steel|"Damascus" blades]], for example, was taken by the [[Arab]]s from the [[Persian people|Persians]], and by the Persians from India."}} ===The philosopher's stone and the rise of alchemy=== {{main|Alchemy}} [[Image:William Fettes Douglas - The Alchemist.jpg|thumb|left|200px|"Renel the Alchemist", by Sir William Douglas, 1853]] Many people were interested in finding a method that could convert cheaper metals into gold. The material that would help them do this was rumored to exist in what was called the [[philosopher's stone]]. This led to the [[protoscience]] called [[alchemy]]. Alchemy was practiced by many cultures throughout history and often contained a mixture of philosophy, mysticism, and protoscience.{{Fact|date=August 2007}} Alchemy not only sought to turn base metals into gold, but especially in a Europe rocked by [[bubonic plague]], there was hope that alchemy would lead to the development of medicines to improve people's health. The [[holy grail]] of this strain of alchemy was in the attempts made at finding the [[elixir of life]], which promised eternal youth. Neither the elixir nor the philosopher's stone were ever found. Also, characteristic of alchemists was the belief that there was in the air an "ether" which breathed life into living things.{{Fact|date=August 2007}} Practitioners of alchemy included [[Isaac Newton]], who remained one throughout his life. ===Problems encountered with alchemy=== There were several problems with alchemy, as seen from today's standpoint. There was no systematic naming system for new compounds, and the language was esoteric and vague to the point that the terminologies meant different things to different people. In fact, according to ''The Fontana History of Chemistry'' (Brock, 1992): <blockquote> The language of alchemy soon developed an arcane and secretive technical vocabulary designed to conceal information from the uninitiated. To a large degree, this language is incomprehensible to us today, though it is apparent that readers of [[Geoffery Chaucer]]'s [[The Canon's Yeoman's Prologue and Tale|Canon's Yeoman's Tale]] or audiences of [[Ben Jonson]]'s [[The Alchemist (play)|The Alchemist]] were able to construe it sufficiently to laugh at it.<ref> {{cite book | last = Brock | first = William H. | title = The Fontana History of Chemistry | publisher = Fontana Press | date = 1992 | location = London, England | pages = 32-33 }} </ref> </blockquote> Chaucer's tale exposed the more fraudulent side of alchemy, especially the manufacture of counterfeit gold from cheap substances. Soon after Chaucer, [[Dante Alighieri]] also demonstrated an awareness of this fraudulence, causing him to consign all alchemists to the [[Inferno]] in his writings. Soon after, in 1317, the [[Avignon]] [[Pope John XXII]] ordered all alchemists to leave France for making counterfeit money. A law was passed in England in 1403 which made the "multiplication of metals" punishable by death. Despite these and other apparently extreme measures, alchemy did not die. Royalty and privileged classes still sought to discover the philosopher's stone and the elixir of life for themselves.<ref> {{cite book | last = Brock | first = William H. | title = The Fontana History of Chemistry | publisher = Fontana Press | date = 1992 | location = London, England }} </ref> There was also no agreed-upon scientific method for making experiments reproducible. Indeed many alchemists included in their methods irrelevant information such as the timing of the tides or the phases of the moon. The esoteric nature and codified vocabulary of alchemy appeared to be more useful in concealing the fact that they could not be sure of very much at all. As early as the 14th century, cracks seemed to grow in the facade of alchemy; and people became sceptical.{{Fact|date=August 2007}} Clearly, there needed to be a scientific method where experiments can be repeated by other people, and results needed to be reported in a clear language that laid out both what is known and unknown. ==From Alchemy to Chemistry== ===Early chemists=== {{see also|Alchemy and chemistry in Islam}} The development of the modern [[scientific method]] was slow and arduous, but an early scientific method for chemistry began emerging among early [[Muslim]] chemists, beginning with the 9th century chemist [[Geber]], who is "considered by many to be the father of chemistry".<ref>{{citation|first=Zygmunt S.|last=Derewenda|year=2007|title=On wine, chirality and crystallography|journal=Acta Crystallographica Section A: Foundations of Crystallography|volume=64|pages=246-258 [247]}}</ref><ref> John Warren (2005). "War and the Cultural Heritage of Iraq: a sadly mismanaged affair", ''Third World Quarterly'', Volume 26, Issue 4 & 5, p. 815-830. </ref><ref>Dr. A. Zahoor (1997), [http://www.unhas.ac.id/~rhiza/saintis/haiyan.html JABIR IBN HAIYAN (Jabir)], [[University of Indonesia]]</ref><ref>Paul Vallely, [http://news.independent.co.uk/world/science_technology/article350594.ece How Islamic inventors changed the world], ''[[The Independent]]''</ref> He invented and named the [[alembic]] (al-anbiq), chemically analyzed many [[chemical substance]]s, composed [[Lapidary|lapidaries]], distinguished between [[alkali]]s and [[acid]]s, and manufactured hundreds of [[drug]]s.<ref>[[Will Durant]] (1980). ''The Age of Faith ([[The Story of Civilization]], Volume 4)'', p. 162-186. Simon & Schuster. ISBN 0671012002.</ref> Among other influential Muslim chemists, [[Ja'far al-Sadiq]]<ref name=Strasburg>Research Committee of [[University of Strasbourg|Strasburg University]], ''Imam Jafar Ibn Muhammad As-Sadiq A.S. The Great Muslim Scientist and Philosopher'', translated by Kaukab Ali Mirza, 2000. Willowdale Ont. ISBN 0969949014.</ref> and [[Al-Kindi|Alkindus]],<ref>Felix Klein-Frank (2001), "Al-Kindi", in [[Oliver Leaman]] & [[Hossein Nasr]], ''History of Islamic Philosophy'', p. 174. London: [[Routledge]].</ref> [[Abū al-Rayhān al-Bīrūnī]],<ref>Michael E. Marmura (1965). "''An Introduction to Islamic Cosmological Doctrines. Conceptions of Nature and Methods Used for Its Study by the Ikhwan Al-Safa'an, Al-Biruni, and Ibn Sina'' by Seyyed [[Hossein Nasr]]", ''Speculum'' '''40''' (4), p. 744-746.</ref> [[Avicenna]]<ref>[[Robert Briffault]] (1938). ''The Making of Humanity'', p. 196-197.</ref> and [[Ibn Khaldun]] refuted the practice of alchemy and the theory of the [[Philosopher's stone|transmutation of metals]]; and [[Nasīr al-Dīn al-Tūsī|Tusi]] described an early version of the [[conservation of mass]], noting that a body of [[matter]] is able to change but is not able to disappear.<ref>Farid Alakbarov (Summer 2001). [http://azer.com/aiweb/categories/magazine/92_folder/92_articles/92_tusi.html A 13th-Century Darwin? Tusi's Views on Evolution], ''Azerbaijan International'' '''9''' (2).</ref> [[Muhammad ibn Zakarīya Rāzi|Rhazes]] refuted [[Aristotle]]'s theory of four [[classical element]]s for the first time and set up the firm foundations of modern chemistry, using the laboratory in the modern sense, designing and describing more than twenty instruments, many parts are still in use today. Such as a crucible, decensory, cucurbit or retort for distillation, and the head of a still with a delivery tube (ambiq, Latin alembic), various types of furnace or stove.<ref>G. Stolyarov II (2002), "Rhazes: The Thinking Western Physician", ''The Rational Argumentator'', Issue VI.</ref> For the more honest practitioners in Europe, alchemy was an intellectual pursuit, and over time, they got better at it. [[Paracelsus]] (1493-1541), for example, rejected the 4-elemental theory and with only a vague understanding of his chemicals and medicines, formed a hybrid of alchemy and science in what was to be called [[iatrochemistry]]. Paracelsus was not perfect in making his experiments truly scientific. For example, as an extension of his theory that new compounds could be made by combining mercury with sulfur, he once made what he thought was "oil of sulfur". This was actually [[dimethyl ether]], which had neither mercury nor sulfur.{{Fact|date=August 2007}} [[Image:Robert Boyle 0001.jpg|thumb|250px|[[Robert Boyle]], one of the co-founders of modern chemistry through his use of proper experimentation, which further separated chemistry from alchemy]] [[Robert Boyle]] (1627–1691) is considered to have refined the modern scientific method for alchemy and to have separated chemistry further from alchemy.{{Fact|date=August 2007}} Robert Boyle was an atomist, but favoured the word ''corpuscle'' over ''atoms''. He comments that the finest division of matter where the properties are retained is at the level of corpuscles. Boyle was credited with the discovery of [[Boyle's Law]]. He is also credited for his landmark publication ''[[The Sceptical Chymist]]'', where he attempts to develop an [[atomic theory]] of matter, with no small degree of success. Despite all these advances, the person celebrated as the "[[People known as the father or mother of something|father of modern chemistry]]" is [[Antoine Lavoisier]] who developed his law of [[Conservation of mass]] in 1789, also called ''Lavoisier's Law''.{{Fact|date=August 2007}} With this, Chemistry was allowed to have a strict quantitative nature, allowing reliable predictions to be made. ===Antoine Lavoisier=== [[Image:David - Portrait of Monsieur Lavoisier and His Wife.jpg|thumb|left|250px|''Portrait of Monsieur Lavoisier and his Wife'', by [[Jacques-Louis David]]]] Although the archives of chemical research draw upon work from ancient [[Babylonia]], [[Ancient Egypt|Egypt]], and especially the [[Arab]]s and [[Persian people|Persians]] after [[Islam]], modern chemistry flourished from the time of [[Antoine Lavoisier]], who is regarded as the "[[People known as the father or mother of something|father of modern chemistry]]", particularly for his discovery of the law of [[conservation of mass]], and his refutation of the [[phlogiston theory]] of [[combustion]] in 1783. (Phlogiston was supposed to be an imponderable substance liberated by flammable materials in burning.) [[Mikhail Lomonosov]] independently established a tradition of chemistry in [[Russia]] in the 18th century.{{Fact|date=August 2007}} Lomonosov also rejected the phlogiston theory, and anticipated the [[kinetic theory]] of gases.{{Fact|date=August 2007}} He regarded heat as a form of motion, and stated the idea of conservation of matter. ===The vitalism debate and organic chemistry=== After the nature of combustion (see [[oxygen]]) was settled, another dispute, about [[vitalism]] and the essential distinction between organic and inorganic substances, was revolutionized by [[Friedrich Wöhler]]'s accidental synthesis of [[urea]] from inorganic substances in 1828. Never before had an organic [[Chemical compound|compound]] been synthesized from inorganic material.{{Fact|date=August 2007}} This opened a new research field in chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The most important among them are [[mauve]], [[magenta]], and other synthetic [[dye]]s, as well as the widely used drug [[aspirin]]. The discovery also contributed greatly to the theory of [[isomerism]].{{Fact|date=August 2007}} ===Disputes about atomism after Lavoisier=== [[Image:Dalton John Chantrey bust.jpg|right|150px|thumb|Bust of Dalton by [[Francis Legatt Chantrey|Chantrey]]]] Throughout the 19th century, chemistry was divided between those who followed the [[atomic theory]] of [[John Dalton]] and those who did not, such as [[Wilhelm Ostwald]] and [[Ernst Mach]].<ref name="pullman"> {{cite book | last = Pullman | first = Bernard | translator = Reisinger, Axel | title = The Atom in the History of Human Thought | publisher = Oxford University Press Inc | date = 2004 | location = USA }} </ref> Although such proponents of the atomic theory as [[Amedeo Avogadro]] and [[Ludwig Boltzmann]] made great advances in explaining the behavior of [[gas]]es, this dispute was not finally settled until [[Jean Perrin]]'s experimental investigation of [[Albert Einstein|Einstein]]'s atomic explanation of [[Brownian motion]] in the first decade of the 20th century.<ref name="pullman"/> Well before the dispute had been settled, many had already applied the concept of atomism to chemistry. A major example was the [[ion]] theory of [[Svante Arrhenius]] which anticipated ideas about atomic substructure that did not fully develop until the 20th century. [[Michael Faraday]] was another early worker, whose major contribution to chemistry was [[history of electrochemistry|electrochemistry]], in which (among other things) a certain quantity of electricity during [[electrolysis]] or [[electrodeposition]] of metals was shown to be associated with certain quantities of chemical elements, and fixed quantities of the elements therefore with each other, in specific ratios.{{Fact|date=August 2007}} These findings, like those of Dalton's combining ratios, were early clues to the atomic nature of matter. ==The periodic table== {{main|History of the periodic table}} [[Image:Дмитрий Иванович Менделеев 4.gif|left]] For many decades, the list of known chemical elements had been [[List of chemical elements by their discovery#19th century|steadily increasing]]. A great breakthrough in making sense of this long list (as well as in understanding the internal structure of atoms as discussed below) was [[Dmitri Mendeleev]] and [[Lothar Meyer]]'s development of the [[periodic table]], and particularly Mendeleev's use of it to predict the existence and the properties of [[germanium]], [[gallium]], and [[scandium]], which Mendeleev called [[Mendeleev's predicted elements|ekasilicon, ekaaluminium, and ekaboron]] respectively. Mendeleev made his prediction in 1870; gallium was discovered in 1875, and was found to have roughly the same properties that Mendeleev predicted for it.{{Fact|date=August 2007}} ==The modern definition of chemistry== Classically, before the 20th century, chemistry was defined as the science of the nature of matter and its transformations. It was therefore clearly distinct from physics which was not concerned with such dramatic transformation of matter. Moreover, in contrast to physics, chemistry was not using much of mathematics. Even some were particularly reluctant to using mathematics within chemistry. For example, [[Auguste Comte]] wrote in 1830: :''Every attempt to employ mathematical methods in the study of chemical questions must be considered profoundly irrational and contrary to the spirit of chemistry.... if mathematical analysis should ever hold a prominent place in chemistry -- an aberration which is happily almost impossible -- it would occasion a rapid and widespread degeneration of that science.'' However, in the second part of the 19th century, the situation changed and [[August Kekule]] wrote in 1867: :''I rather expect that we shall someday find a mathematico-mechanical explanation for what we now call atoms which will render an account of their properties.'' After the discovery by [[Ernest Rutherford]] and [[Niels Bohr]] of the atomic structure in 1912, and by [[Maria Sklodowska-Curie|Marie]] and [[Pierre Curie]] of [[radioactivity]], scientists had to change their viewpoint on the nature of matter. The experience acquired by chemists was no longer pertinent to the study of the whole nature of matter but only to aspects related to the [[electron cloud]] surrounding the atomic [[Atomic nucleus|nuclei]] and the movement of the latter in the [[electric field]] induced by the former (see [[Born-Oppenheimer approximation]]). The range of chemistry was thus restricted to the nature of matter around us in conditions which are not too far from [[standard conditions for temperature and pressure]] and in cases where the exposure to radiation is not too different from the natural [[microwave]], [[visible]] or [[UV]] radiations on Earth. Chemistry was therefore re-defined as the science of matter that deals with the composition, structure, and properties of substances and with the transformations that they undergo.{{Fact|date=August 2007}} However the meaning of matter used here relates explicitly to substances made of atoms and molecules, disregarding the matter within the atomic nuclei and its nuclear reaction or matter within highly ionized plasmas. Nevertheless the field of chemistry is still, on our human scale, very broad and the claim that ''chemistry is everywhere'' is accurate. ==Quantum chemistry== {{main|Quantum chemistry}} Some view the birth of quantum chemistry in the discovery of the [[Schrödinger equation]] and its application to [[hydrogen atom]] in 1926.{{Fact|date=August 2007}} However, the 1927 article of [[Walter Heitler]] and [[Fritz London]]<ref>[[Walter Heitler|W. Heitler]] and [[Fritz London|F. London]], ''Wechselwirkung neutraler Atome und Homöopolare Bindung nach der Quantenmechanik'', Z. Physik, 44, 455 (1927).</ref> is often recognised as the first milestone in the history of quantum chemistry.{{Fact|date=August 2007}} This is the first application of [[quantum mechanics]] to the diatomic [[hydrogen]] molecule, and thus to the phenomenon of the [[chemical bond]]. In the following years much progress was accomplished by [[Edward Teller]], [[Robert S. Mulliken]], [[Max Born]], [[J. Robert Oppenheimer]], [[Linus Pauling]], [[Erich Hückel]], [[Douglas Hartree]], [[Vladimir Aleksandrovich Fock]], to cite a few.{{Fact|date=August 2007}} Still, skepticism remained as to the general power of quantum mechanics applied to complex chemical systems.{{Fact|date=August 2007}} The situation around 1930 is described by [[Paul Dirac]]:<ref>[[Paul Dirac|P.A.M. Dirac]], ''Quantum Mechanics of Many-Electron Systems'', Proc. R. Soc. London, A 123, 714 (1929).</ref> {{quote|"The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. It therefore becomes desirable that approximate practical methods of applying quantum mechanics should be developed, which can lead to an explanation of the main features of complex atomic systems without too much computation.'' Hence the quantum mechanical methods developed in the 1930s and 1940s are often referred to as theoretical [[molecular physics|molecular]] or [[atomic physics]] to underline the fact that they were more the application of quantum mechanics to chemistry and [[spectroscopy]] than answers to chemically relevant questions."}} In the 1940s many physicists turned from [[molecular physics|molecular]] or [[atomic physics]] to [[nuclear physics]] (like [[J. Robert Oppenheimer]] or [[Edward Teller]]). In 1951, a milestone article in quantum chemistry is the seminal paper of [[Clemens C. J. Roothaan]] on [[Roothaan equations]].<ref>[[Clemens C. J. Roothaan|C.C.J. Roothaan]], ''A Study of Two-Center Integrals Useful in Calculations on Molecular Structure'', J. Chem. Phys., 19, 1445 (1951).</ref> It opened the avenue to the solution of the [[self-consistent field]] equations for small molecules like [[hydrogen]] or [[nitrogen]]. Those computations were performed with the help of tables of integrals which were computed on the most advanced computers of the time.{{Fact|date=August 2007}} ==Molecular biology and biochemistry== {{main|History of molecular biology|History of biochemistry}} By the mid 20th century, in principle, the integration of physics and chemistry was extensive, with chemical properties explained as the result of the [[electron]]ic structure of the [[atom]]; [[Linus Pauling]]'s book on ''The Nature of the Chemical Bond'' used the principles of quantum mechanics to deduce [[bond angle]]s in ever-more complicated molecules. However, though some principles deduced from quantum mechanics were able to predict qualitatively some chemical features for biologically relevant molecules, they were, till the end of the 20th century, more a collection of rules, observations, and recipes than rigorous [[ab initio]] quantitative methods.{{Fact|date=August 2007}} [[Image:DNA chemical structure.svg|thumb|right|200px|Diagrammatic representation of some key structural features of DNA]] This heuristic approach triumphed in 1953 when [[James Watson]] and [[Francis Crick]] deduced the double helical structure of [[DNA]] by constructing models constrained by and informed by the knowledge of the chemistry of the constituent parts and the [[X-ray diffraction]] patterns obtained by [[Rosalind Franklin]].<ref>[http://www.nature.com/nature/dna50/watsoncrick.pdf Watson, J. and Crick, F., "Molecular Structure of Nucleic Acids"] ''Nature, [[April 25]], [[1953]], p 737–8 ''</ref> This discovery lead to an explosion of research into the [[biochemistry]] of life. In the same year, the [[Miller-Urey experiment]] demonstrated that basic constituents of [[protein]], simple [[amino acid]]s, could themselves be built up from simpler molecules in a [[simulation]] of primordial [[Process (science)|processes]] on Earth. Though many questions remain about the true nature of the origin of life, this was the first attempt by chemists to study hypothetical processes in the laboratory under controlled conditions.{{Fact|date=August 2007}} In 1983 [[Kary Mullis]] devised a method for the in-vitro amplification of DNA, known as the [[polymerase chain reaction]] (PCR), which revolutionized the chemical processes used in the laboratory to manipulate it. PCR could be used to synthesize specific pieces of DNA and made possible the [[DNA sequencing|sequencing of DNA]] of organisms, which culminated in the huge [[human genome project]].{{Fact|date=August 2007}} ==Chemical industry== {{main|Chemical industry}} The later part of the nineteenth century saw a huge increase in the exploitation of [[petroleum]] extracted from the earth for the production of a host of chemicals and largely replaced the use of [[whale oil]], [[coal tar]] and [[naval stores]] used previously. Large scale production and [[oil refinery|refinement of petroleum]] provided feedstocks for [[liquid fuels]] such as [[gasoline]] and [[diesel]], [[solvents]], [[lubricants]], [[asphalt]], [[waxes]], and for the production of many of the common materials of the modern world, such as synthetic [[fibers]], [[plastic]]s, [[paints]], [[detergent]]s, [[pharmaceuticals]], [[adhesives]] and [[ammonia]] as [[fertilizer]] and for other uses. Many of these required new [[catalysts]] and the utilization of [[chemical engineering]] for their cost-effective production.{{Fact|date=August 2007}} In the mid-twentieth century, control of the electronic structure of [[semiconductor]] materials was made precise by the creation of large ingots of extremely pure single crystals of [[silicon]] and [[germanium]]. Accurate control of their chemical composition by doping with other elements made the production of the solid state [[transistor]] in 1951 and made possible the production of tiny [[integrated circuit]]s for use in electronic devices, especially [[computers]], which revolutionized the world.{{Fact|date=August 2007}} ==See also== ===Histories and timelines=== *[[Atomic theory]] *[[History of electrochemistry]] *[[History of the molecule]] *[[History of molecular biology]] *[[History of the periodic table]] *[[History of physics]] *[[History of science and technology]] *[[History of thermodynamics]] *[[History of energy]] *[[Discoveries of the chemical elements]] *[[Timeline of chemistry]] *[[Timeline of materials technology]] *[[Timeline of microphysics]] *[[Timeline of thermodynamics, statistical mechanics, and random processes]] *[[List of years in science]] *[[Nobel Prize in chemistry]] ===Chemists=== ''listed chronologically:'' *[[List of chemists]] *[[Joseph Black]], 1728-1799 *[[Joseph Priestley]], 1733-1804 *[[Carl Wilhelm Scheele]], 1742-1786 *[[Alessandro Volta]], 1745-1827 *[[Jacques Charles]], 1746-1823 *[[Claude Louis Berthollet]], 1748-1822 *[[Joseph-Louis Gay-Lussac]], 1778-1850 *[[Humphry Davy]], 1778-1829 *[[Jöns Jakob Berzelius]], inventor of modern chemical notation, 1779-1848 *[[Justus von Liebig]], 1803-1873 *[[Louis Pasteur]], 1822-1895 *[[Stanislao Cannizzaro]], 1826-1910 *[[Friedrich August Kekulé von Stradonitz]], 1829-1896 *[[Willard Gibbs]], 1839-1903 *[[J. H. van 't Hoff]], 1852-1911 *[[Marie Curie]], 1867-1934 *[[Victor Grignard]], 1871-1935 *[[Gilbert N. Lewis]], 1875-1946 *[[Irving Langmuir]], 1881-1957 *[[Glenn T. Seaborg]], 1912-1999 ==Notes== {{reflist}} ==References== *[http://web.lemoyne.edu/~giunta/papers.html Selected classic papers from the history of chemistry] *[http://www.liv.ac.uk/Chemistry/Links/refbiog.html Biographies of chemists] *Eric R. Scerri, The Periodic Table: Its Story and Its Significance, Oxford University Press, 2006. ==External links== * [http://www.chemislab.com/chemists-of-the-past/ ChemisLab] - Chemists of the Past * [http://www.ambix.org/ SHAC: Society for the History of Alchemy and Chemistry] [[Category:History of chemistry|*]] [[Category:Chemistry]] {{Link FA|pt}} [[ar:تاريخ الكيمياء]] [[de:Geschichte der Chemie]] [[es:Historia de la química]] [[fr:Histoire de la chimie]] [[id:Sejarah kimia]] [[it:Storia della chimica]] [[nl:Geschiedenis van de scheikunde]] [[ja:化学の歴史]] [[no:Kjemiens historie]] [[pl:Historia chemii]] [[pt:História da química]] [[ro:Istoria chimiei]] [[ru:История химии]] [[sv:Kemins historia]] [[uk:Історія хімії]]