Themes > Science > Chemistry > About Chemistry Generalities > Chemistry: Chronology

3000 BC
Egyptians are producing bronze – an alloy of copper and tin.
c. 450 BC Greek philosopher Empedocles proposes that all substances are made up of a combination of four elements – earth, air, fire, and water – an idea that is developed by Plato and Aristotle and persists for over 2,000 years.
c. 400 BC Greek philosopher Democritus theorizes that matter consists ultimately of tiny, indivisible particles, atomos.
AD 1 Gold, silver, copper, lead, iron, tin, and mercury are known.
200 The techniques of solution, filtration, and distillation are known.
7th–17th centuries Chemistry is dominated by alchemy, the attempt to transform nonprecious metals such as lead and copper into gold. Though misguided, it leads to the discovery of many new chemicals and techniques, such as sublimation and distillation.
12th century Alcohol is first distilled in Europe.
1242 Gunpowder is introduced to Europe from the Far East.
1620 The scientific method of reasoning is expounded by Francis Bacon in his Novum Organum.
1650 Leyden University in the Netherlands sets up the first chemistry laboratory.
1661 Robert Boyle defines an element as any substance that cannot be broken down into still simpler substances and asserts that matter is composed of 'corpuscles' (atoms) of various sorts and sizes, capable of arranging themselves into groups, each of which constitutes a chemical substance.
1662 Boyle describes the inverse relationship between the volume and pressure of a fixed mass of gas (Boyle's law).
1697 Georg Stahl proposes the erroneous theory that substances burn because they are rich in a substance called phlogiston.
1755 Joseph Black discovers carbon dioxide.
1774 Joseph Priestley discovers oxygen, which he calls 'dephlogisticated air'. Antoine Lavoisier demonstrates his law of conservation of mass.
1777 Lavoisier shows air to be made up of a mixture of gases, and shows that one of these – oxygen – is the substance necessary for combustion (burning) and rusting to take place.
1781 Henry Cavendish shows water to be a compound.
1792 Alessandra Volta demonstrates the electrochemical series.
1807 Humphry Davy passes an electric current through molten compounds (the process of electrolysis) in order to isolate elements, such as potassium, that have never been separated by chemical means. Jöns Berzelius proposes that chemicals produced by living creatures should be termed 'organic'.
1808 John Dalton publishes his atomic theory, which states that every element consists of similar indivisible particles – called atoms – which differ from the atoms of other elements in their mass; he also draws up a list of relative atomic masses. Joseph Gay-Lussac announces that the volumes of gases that combine chemically with one another are in simple ratios.
1811 Amedeo Avogadro's hypothesis on the relation between the volume and number of molecules of a gas, and its temperature and pressure, is published.
1813–14 Berzelius devises the chemical symbols and formulae still used to represent elements and compounds.
1828 Franz Wöhler converts ammonium cyanate into urea – the first synthesis of an organic compound from an inorganic substance.
1832–33 Michael Faraday expounds the laws of electrolysis, and adopts the term 'ion' for the particles believed to be responsible for carrying current.
1846 Thomas Graham expounds his law of diffusion.
1853 Robert Bunsen invents the Bunsen burner.
1858 Stanislao Cannizzaro differentiates between atomic and molecular weights (masses).
1861 Organic chemistry is defined by German chemist Friedrich Kekulé as the chemistry of carbon compounds.
1864 John Newlands devises the first periodic table of the elements.
1869 Dmitri Mendeleyev expounds his periodic table of the elements (based on atomic mass), leaving gaps for elements that have not yet been discovered.
1874 Jacobus van't Hoff suggests that the four bonds of carbon are arranged tetrahedrally, and that carbon compounds can therefore be three-dimensional and asymmetric.
1884 Swedish chemist Svante Arrhenius suggests that electrolytes (solutions or molten compounds that conduct electricity) dissociate into ions, atoms or groups of atoms that carry a positive or negative charge.
1894 William Ramsey and Lord Rayleigh discover the first inert gases, argon.
1897 The electron is discovered by J J Thomson.
1901 Mikhail Tsvet invents paper chromatography as a means of separating pigments.
1909 Sören Sörensen devises the pH scale of acidity.
1912 Max von Laue shows crystals to be composed of regular, repeating arrays of atoms by studying the patterns in which they diffract X-rays.
1913–14 Henry Moseley equates the atomic number of an element with the positive charge on its nuclei, and draws up the periodic table, based on atomic number, that is used today.
1916 Gilbert Newton Lewis explains covalent bonding between atoms as a sharing of electrons.
1927 Nevil Sidgwick publishes his theory of valency, based on the numbers of electrons in the outer shells of the reacting atoms.
1930 Electrophoresis, which separates particles in suspension in an electric field, is invented by Arne Tiselius.
1932 Deuterium (heavy hydrogen), an isotope of hydrogen, is discovered by Harold Urey.
1940 Edwin McMillan and Philip Abelson show that new elements with a higher atomic number than uranium can be formed by bombarding uranium with neutrons, and synthesize the first transuranic element, neptunium.
1942 Plutonium is first synthesized by Glenn T Seaborg and Edwin McMillan.
1950 Derek Barton deduces that some properties of organic compounds are affected by the orientation of their functional groups (the study of which becomes known as conformational analysis).
1954 Einsteinium and fermium are synthesized.
1955 Ilya Prigogine describes the thermodynamics of irreversible processes (the transformations of energy that take place in, for example, many reactions within living cells).
1962 Neil Bartlett prepares the first compound of an inert gas, xenon hexafluoroplatinate; it was previously believed that inert gases could not take part in a chemical reaction.
1965 Robert B Woodward synthesizes complex organic compounds.
1981 Quantum mechanics is applied to predict the course of chemical reactions by US chemist Roald Hoffmann and Kenichi Fukui of Japan.
1982 Element 109, unnilennium, is synthesized.
1985 Fullerenes, a new class of carbon solids made up of closed cages of carbon atoms, are discovered by Harold Kroto and David Walton at the University of Sussex, England.
1987 US chemists Donald Cram and Charles Pederson, and Jean-Marie Lehn of France create artificial molecules that mimic the vital chemical reactions of life processes.
1990 Jean-Marie Lehn, Ulrich Koert, and Margaret Harding report the synthesis of a new class of compounds, called nucleohelicates, that mimic the double helical structure of DNA, turned inside out.
1993 US chemists at the University of California and the Scripps Institute synthesize rapamycin, one of a group of complex, naturally occurring antibiotics and immunosuppressants that are being tested as anticancer agents.
1994 Elements 110 (ununnilium) and 111 (unununium) are discovered at the GSI heavy-ion cyclotron, Darmstadt, Germany.
1995 German chemists build the largest ever wheel molecule, made up of 154 molybdenum atoms surrounded by oxygen atoms. It has a relative molecular mass of 24,000 and is soluble in water.
1996 Element 112 is discovered at the GSI heavy-ion cyclotron, Darmstadt, Germany.
1997 The International Union of Pure and Applied Chemistry (IUPAC) states that elements 104–109 should be named rutherfordium (104), dubnium (105), seaborgium (106), bohrium (107), hassium (108), and meitnerium (109).


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