Prior to the acceptance of the scientific method and its application to the field of chemistry, it is somewhat controversial to consider many of the people listed below as "chemists" in the modern sense of the word. However, the ideas of certain great thinkers, either for their prescience, or for their wide and long-term acceptance, bear listing here.
c. 3000 BCEgyptians formulate the theory of the Ogdoad, or the "primordial
forces", from which all was formed. These were the elements of chaos, numbered in eight, that existed before the creation of the sun.
c. 1200 BCTapputi-Belatikallim, a perfume-maker and early chemist, was mentioned in a cuneiform tablet in Mesopotamia.
c. 450 BCEmpedocles asserts that all things are composed of four primal elements: earth, air, fire, and water, whereby two active and opposing forces, love and hate, or affinity and antipathy, act upon these elements, combining and separating them into infinitely varied forms.
c. 440 BCLeucippus and Democritus propose the idea of the atom, an indivisible particle that all matter is made of. This idea is largely rejected by natural philosophers in favor of the Aristotlean view (see below).
c. 360 BCPlato coins term ‘elements’ (
stoicheia) and in his dialogue
Timaeus, which includes a discussion of the composition of inorganic and organic bodies and is a rudimentary treatise on chemistry, assumes that the minute particle of each element had a special geometric shape:
tetrahedron (fire),
octahedron (air),
icosahedron (water), and
cube (earth).
c. 350 BCAristotle, expanding on Empedocles, proposes idea of a substance as a combination of
matter and
form. Describes theory of the Five Elements, fire, water, earth, air, and aether. This theory is largely accepted throughout the western world for over 1000 years.
c. 50 BCLucretius publishes
De Rerum Natura, a poetic description of the ideas of
atomism.
c. 300Zosimos of Panopolis writes some of the oldest known books on alchemy, which he defines as the study of the composition of waters, movement, growth, embodying and disembodying, drawing the spirits from bodies and bonding the spirits within bodies.
c. 770Abu Musa Jabir ibn Hayyan (aka Geber), an Arab/Persian alchemist who is "considered by many to be the father of chemistry", develops an early experimental method for chemistry, and isolates numerous acids, including
hydrochloric acid, nitric
acid, citric acid,
acetic acid,
tartaric acid, and
aqua regia.
c. 1000Abū al-Rayhān al-Bīrūnī and
Avicenna, both Persian chemists, refute the practice of alchemy and the theory of the transmutation of metals.
c. 1167Magister Salernus of the School of Salerno makes the first references to the distillation of wine.
c. 1220Robert Grosseteste publishes several Aristotelian commentaries where he lays out an early framework for the scientific method.
c 1250Tadeo Alderotti develops
fractional distillation, which is much more effective than its predecessors.
c 1260St
Albertus Magnus discovers
arsenic and
silver nitrate. He also made one of the first references to
sulfuric acid.
c. 1267Roger Bacon publishes
Opus Maius, which among other things, proposes an early form of the scientific method, and contains results of his experiments with
gunpowder.
c. 1310Pseudo-Geber, an anonymous Spanish alchemist who wrote under the name of Geber, publishes several books that establish the long-held theory that all metals were composed of various proportions of
sulfur and
mercury. He is one of the first to describe nitric acid, aqua regia, and aqua fortis.
c. 1530Paracelsus develops the study of
iatrochemistry, a subdiscipline of alchemy dedicated to extending life, thus being the roots of the modern
pharmaceutical industry. It is also claimed that he is the first to use the word "chemistry".
1597Andreas Libavius publishes
Alchemia, a prototype chemistry textbook.
17th and 18th centuries
1605Sir Francis Bacon publishes
The Proficience and Advancement of Learning, which contains a description of what would later be known as the scientific method.
1605Michal Sedziwój publishes the alchemical treatise
A New Light of Alchemy which proposed the existence of the "food of life" within air, much later recognized as
oxygen.
1615Jean Beguin publishes the
Tyrocinium Chymicum, an early chemistry textbook, and in it draws the first-ever
chemical equation.
1637René Descartes publishes
Discours de la méthode, which contains an outline of the scientific method.
1648Posthumous publication of the book
Ortus medicinae by
Jan Baptist van Helmont, which is cited by some as a major transitional work between alchemy and chemistry, and as an important influence on
Robert Boyle. The book contains the results of numerous experiments and establishes an early version of the law of conservation of mass.
1661Robert Boyle publishes
The Sceptical Chymist, a treatise on the distinction between chemistry and alchemy. It contains some of the earliest modern ideas of
atoms,
molecules, and
chemical reaction, and marks the beginning of the history of modern chemistry.
1662Robert Boyle proposes
Boyle's law, an experimentally based description of the behavior of
gases, specifically the relationship between
pressure and
volume.
1735Swedish chemist
Georg Brandt analyzes a dark blue pigment found in copper ore. Brandt demonstrated that the pigment contained a new element, later named
cobalt.
1754Joseph Black isolates
carbon dioxide, which he called "fixed air".
1757Louis Claude Cadet de Gassicourt, while investigating arsenic compounds, creates
Cadet's fuming liquid, later discovered to be
cacodyl oxide, considered to be the first synthetic organometallic compound.
1758Joseph Black formulates the concept of
latent heat to explain the
thermochemistry of phase changes.
1766Henry Cavendish discovers
hydrogen as a colorless, odourless gas that burns and can form an explosive mixture with air.
1773–1774Carl Wilhelm Scheele and
Joseph Priestley independently isolate oxygen, called by Priestley "dephlogisticated air" and Scheele "fire air".
1778Antoine Lavoisier, considered "The father of modern chemistry", recognizes and names oxygen, and recognizes its importance and role in combustion.
1787Antoine Lavoisier publishes
Méthode de nomenclature chimique, the first modern system of chemical nomenclature.
1787Jacques Charles proposes
Charles's law, a corollary of
Boyle's law, describes relationship between
temperature and volume of a gas.
1789Antoine Lavoisier publishes
Traité Élémentaire de Chimie, the first modern chemistry textbook. It is a complete survey of (at that time) modern chemistry, including the first concise definition of the law of conservation of mass, and thus also represents the founding of the discipline of
stoichiometry or quantitative chemical analysis.
1797Joseph Proust proposes the
law of definite proportions, which states that elements always combine in small, whole number ratios to form compounds.
1800Alessandro Volta devises the first chemical battery, thereby founding the discipline of
electrochemistry.
1801John Dalton proposes
Dalton's law, which describes relationship between the components in a mixture of gases and the relative pressure each contributes to that of the overall mixture.
1805Joseph Louis Gay-Lussac discovers that water is composed of two parts hydrogen and one part oxygen by volume.
1808Joseph Louis Gay-Lussac collects and discovers several chemical and physical properties of air and of other gases, including experimental proofs of Boyle's and
Charles's laws, and of relationships between density and composition of gases.
1808John Dalton publishes
New System of Chemical Philosophy, which contains first modern scientific description of the atomic theory, and clear description of the
law of multiple proportions.
1808Jöns Jakob Berzelius publishes
Lärbok i Kemien in which he proposes modern chemical symbols and notation, and of the concept of relative atomic weight.
1811Amedeo Avogadro proposes
Avogadro's law, that equal volumes of gases under constant temperature and pressure contain equal number of molecules.
1825Friedrich Wöhler and
Justus von Liebig perform the first confirmed discovery and explanation of isomers, earlier named by Berzelius. Working with cyanic acid and fulminic acid, they correctly deduce that isomerism was caused by differing arrangements of atoms within a molecular structure.
1827William Prout classifies biomolecules into their modern groupings: carbohydrates, proteins and lipids.
1828Friedrich Wöhler synthesizes
urea, thereby establishing that organic compounds could be produced from inorganic starting materials, disproving the theory of
vitalism.
1832Friedrich Wöhler and Justus von Liebig discover and explain
functional groups and radicals in relation to
organic chemistry.
1840Germain Hess proposes
Hess's law, an early statement of the law of conservation of energy, which establishes that energy changes in a chemical process depend only on the states of the starting and product materials and not on the specific pathway taken between the two states.
1847Hermann Kolbe obtains acetic acid from completely inorganic sources, further disproving vitalism.
1848Lord Kelvin establishes concept of
absolute zero, the temperature at which all molecular motion ceases.
1849Louis Pasteur discovers that the racemic form of tartaric acid is a mixture of the levorotatory and dextrotatory forms, thus clarifying the nature of
optical rotation and advancing the field of
stereochemistry.
1852August Beer proposes Beer's law, which explains the relationship between the composition of a mixture and the amount of light it will absorb. Based partly on earlier work by
Pierre Bouguer and
Johann Heinrich Lambert, it establishes the
analytical technique known as
spectrophotometry.
1855Benjamin Silliman, Jr. pioneers methods of petroleum cracking, which makes the entire modern
petrochemical industry possible.
1856William Henry Perkin synthesizes Perkin's mauve, the first synthetic dye. Created as an accidental byproduct of an attempt to create
quinine from
coal tar. This discovery is the foundation of the dye synthesis industry, one of the earliest successful chemical industries.
1857Friedrich August Kekulé von Stradonitz proposes that
carbon is tetravalent, or forms exactly four chemical bonds.
1859–1860Gustav Kirchhoff and
Robert Bunsen lay the foundations of
spectroscopy as a means of chemical analysis, which lead them to the discovery of
caesium and
rubidium. Other workers soon used the same technique to discover
indium,
thallium, and
helium.
1860Stanislao Cannizzaro, resurrecting Avogadro's ideas regarding diatomic molecules, compiles a table of atomic weights and presents it at the 1860
Karlsruhe Congress, ending decades of conflicting atomic weights and molecular formulas, and leading to Mendeleev's discovery of the periodic law.
1862Alexander Parkes exhibits Parkesine, one of the earliest synthetic polymers, at the International Exhibition in London. This discovery formed the foundation of the modern
plastics industry.
1862Alexandre-Emile Béguyer de Chancourtois publishes the telluric helix, an early, three-dimensional version of the
periodic table of the elements.
1864John Newlands proposes the law of octaves, a precursor to the periodic law.
1864Lothar Meyer develops an early version of the periodic table, with 28 elements organized by
valence.
1864Cato Maximilian Guldberg and
Peter Waage, building on Claude Louis Berthollet's ideas, proposed the
law of mass action.
1865Johann Josef Loschmidt determines exact number of molecules in a
mole, later named Avogadro's number.
1865Friedrich August Kekulé von Stradonitz, based partially on the work of Loschmidt and others, establishes structure of
benzene as a six carbon ring with alternating
single and
double bonds.
1865Adolf von Baeyer begins work on
indigo dye, a milestone in modern industrial organic chemistry which revolutionizes the dye industry.
1869Dmitri Mendeleev publishes the first modern periodic table, with the 66 known elements organized by atomic weights. The strength of his table was its ability to accurately predict the properties of as-yet unknown elements.
1873Jacobus Henricus van 't Hoff and
Joseph Achille Le Bel, working independently, develop a model of chemical bonding that explains the chirality experiments of Pasteur and provides a physical cause for optical activity in
chiral compounds.
1876Josiah Willard Gibbs publishes
On the Equilibrium of Heterogeneous Substances, a compilation of his work on thermodynamics and
physical chemistry which lays out the concept of
free energy to explain the physical basis of
chemical equilibria.
1877Ludwig Boltzmann establishes statistical derivations of many important physical and chemical concepts, including
entropy, and distributions of molecular velocities in the gas phase.
1883Svante Arrhenius develops
ion theory to explain conductivity in
electrolytes.
1884Jacobus Henricus van 't Hoff publishes
Études de Dynamique chimique, a seminal study on
chemical kinetics.
1884Hermann Emil Fischer proposes structure of
purine, a key structure in many biomolecules, which he later synthesized in 1898. Also begins work on the chemistry of
glucose and related
sugars.
1884Henry Louis Le Chatelier develops
Le Chatelier's principle, which explains the response of dynamic chemical equilibria to external stresses.
1885Eugene Goldstein names the
cathode ray, later discovered to be composed of electrons, and the canal ray, later discovered to be positive hydrogen ions that had been stripped of their electrons in a cathode ray tube. These would later be named
protons.
1893Alfred Werner discovers the octahedral structure of cobalt complexes, thus establishing the field of coordination chemistry.
1894–1898William Ramsay discovers the noble gases, which fill a large and unexpected gap in the periodic table and led to models of chemical bonding.
1897J. J. Thomson discovers the
electron using the cathode ray tube.
1898Wilhelm Wien demonstrates that canal rays (streams of positive ions) can be deflected by magnetic fields, and that the amount of deflection is proportional to the
mass-to-charge ratio. This discovery would lead to the
analytical technique known as
mass spectrometry.
1898Maria Sklodowska-Curie and
Pierre Curie isolate
radium and
polonium from pitchblende.
c. 1900Ernest Rutherford discovers the source of radioactivity as decaying atoms; coins terms for various types of radiation.
1903Mikhail Semyonovich Tsvet invents
chromatography, an important analytic technique.
1904Hantaro Nagaoka proposes an early nuclear model of the atom, where electrons orbit a dense massive nucleus.
1905Fritz Haber and
Carl Bosch develop the
Haber process for making
ammonia from its elements, a milestone in industrial chemistry with deep consequences in agriculture.
1905Albert Einstein explains
Brownian motion in a way that definitively proves atomic theory.
1907Leo Hendrik Baekeland invents
bakelite, one of the first commercially successful plastics.
1909Robert Millikan measures the charge of individual electrons with unprecedented accuracy through the
oil drop experiment, confirming that all electrons have the same charge and mass.
1909S. P. L. Sørensen invents the pH concept and develops methods for measuring acidity.
1911Antonius van den Broek proposes the idea that the elements on the periodic table are more properly organized by positive nuclear charge rather than atomic weight.
1911The first
Solvay Conference is held in
Brussels, bringing together most of the most prominent scientists of the day. Conferences in physics and chemistry continue to be held periodically to this day.
1911Ernest Rutherford,
Hans Geiger, and
Ernest Marsden perform the gold foil experiment, which proves the nuclear model of the atom, with a small, dense, positive nucleus surrounded by a diffuse electron cloud.
1912William Henry Bragg and William Lawrence Bragg propose
Bragg's law and establish the field of
X-ray crystallography, an important tool for elucidating the crystal structure of substances.
1912Peter Debye develops the concept of
molecular dipole to describe asymmetric charge distribution in some molecules.
1913Niels Bohr introduces concepts of
quantum mechanics to atomic structure by proposing what is now known as the
Bohr model of the atom, where electrons exist only in strictly defined orbitals.
1913Henry Moseley, working from Van den Broek's earlier idea, introduces concept of
atomic number to fix inadequacies of Mendeleev's periodic table, which had been based on atomic weight.
1913Frederick Soddy proposes the concept of
isotopes, that elements with the same chemical properties may have differing atomic weights.
1913J. J. Thomson expanding on the work of Wien, shows that charged subatomic particles can be separated by their mass-to-charge ratio, a technique known as
mass spectrometry.
1916Gilbert N. Lewis publishes "The Atom and the Molecule", the foundation of
valence bond theory.
1921Otto Stern and Walther Gerlach establish concept of quantum mechanical spin in subatomic particles.
1923Gilbert N. Lewis and
Merle Randall publish
Thermodynamics and the Free Energy of Chemical Substances, first modern treatise on
chemical thermodynamics.
1923Gilbert N. Lewis develops the electron pair theory of acid/base reactions.
1924Louis de Broglie introduces the wave-model of atomic structure, based on the ideas of
wave–particle duality.
1925Wolfgang Pauli develops the
exclusion principle, which states that no two electrons around a single nucleus may have the same quantum state, as described by four quantum numbers.
1926Erwin Schrödinger proposes the
Schrödinger equation, which provides a mathematical basis for the wave model of atomic structure.
1927Werner Heisenberg develops the
uncertainty principle which, among other things, explains the mechanics of electron motion around the nucleus.
1927Fritz London and
Walter Heitler apply quantum mechanics to explain covalent bonding in the hydrogen molecule, which marked the birth of
quantum chemistry.
1929Linus Pauling publishes
Pauling's rules, which are key principles for the use of
X-ray crystallography to deduce molecular structure.
1931Erich Hückel proposes
Hückel's rule, which explains when a planar ring molecule will have
aromatic properties.
1931Harold Urey discovers
deuterium by fractionally distilling liquid hydrogen.
1932James Chadwick discovers the
neutron.
1932–1934Linus Pauling and Robert Mulliken quantify
electronegativity, devising the scales that now bear their names.
1935Wallace Carothers leads a team of chemists at
DuPont who invent
nylon, one of the most commercially successful synthetic polymers in history.
1937Carlo Perrier and Emilio Segrè perform the first confirmed synthesis of
technetium-97, the first artificially produced element, filling a gap in the periodic table. Though disputed, the element may have been synthesized as early as 1925 by
Walter Noddack and others.
1937Eugene Houdry develops a method of industrial scale catalytic cracking of petroleum, leading to the development of the first modern oil refinery.
1937Pyotr Kapitsa, John Allen and
Don Misener produce supercooled
helium-4, the first zero-viscosity superfluid, a substance that displays quantum mechanical properties on a macroscopic scale.
1938Otto Hahn discovers the process of
nuclear fission in
uranium and thorium.
1939Linus Pauling publishes
The Nature of the Chemical Bond, a compilation of a decades worth of work on chemical bonding. It is one of the most important modern chemical texts. It explains hybridization theory, covalent bonding and
ionic bonding as explained through electronegativity, and
resonance as a means to explain, among other things, the structure of benzene.
1940Edwin McMillan and Philip H. Abelson identify
neptunium, the lightest and first synthesized
transuranium element, found in the products of uranium
fission. McMillan would found a lab at
Berkeley that would be involved in the discovery of many new elements and isotopes.
1941Glenn T. Seaborg takes over McMillan's work creating new atomic nuclei. Pioneers method of
neutron capture and later through other nuclear reactions. Would become the principal or co-discoverer of nine new chemical elements, and dozens of new isotopes of existing elements.
1945Jacob A. Marinsky,
Lawrence E. Glendenin, and
Charles D. Coryell perform the first confirmed synthesis of
Promethium, filling in the last "gap" in the periodic table.
1945–1946Felix Bloch and
Edward Mills Purcell develop the process of
nuclear magnetic resonance, an analytical technique important in elucidating structures of molecules, especially in organic chemistry.
1951Linus Pauling uses X-ray crystallography to deduce the secondary structure of proteins.
1952Alan Walsh pioneers the field of
atomic absorption spectroscopy, an important quantitative spectroscopy method that allows one to measure specific concentrations of a material in a mixture.
1952Robert Burns Woodward,
Geoffrey Wilkinson, and
Ernst Otto Fischer discover the structure of
ferrocene, one of the founding discoveries of the field of
organometallic chemistry.
1953James D. Watson and
Francis Crick propose the structure of
DNA, opening the door to the field of
molecular biology.
1957Jens Skou discovers Na⁺/K⁺-ATPase, the first ion-transporting enzyme.
1958Max Perutz and
John Kendrew use X-ray crystallography to elucidate a
protein structure, specifically
sperm whale myoglobin.
1962Neil Bartlett synthesizes
xenon hexafluoroplatinate, showing for the first time that the noble gases can form chemical compounds.
1962George Olah observes
carbocations via
superacid reactions.
1964Richard R. Ernst performs experiments that will lead to the development of the technique of
Fourier transform NMR. This would greatly increase the sensitivity of the technique, and open the door for
magnetic resonance imaging or MRI.
1965Robert Burns Woodward and
Roald Hoffmann propose the
Woodward–Hoffmann rules, which use the symmetry of
molecular orbitals to explain the stereochemistry of chemical reactions.
1966Hitoshi Nozaki and
Ryōji Noyori discovered the first example of asymmetric catalysis (
hydrogenation) using a structurally well-defined chiral
transition metal complex.
1970John Pople develops the
Gaussian program greatly easing
computational chemistry calculations.
1971Yves Chauvin offered an explanation of the reaction mechanism of
olefin metathesis reactions.
1975Karl Barry Sharpless and group discover a stereoselective oxidation reactions including
Sharpless epoxidation,
Sharpless asymmetric dihydroxylation, and
Sharpless oxyamination.
1985Harold Kroto,
Robert Curl and
Richard Smalley discover fullerenes, a class of large carbon molecules superficially resembling the
geodesic dome designed by architect R. Buckminster Fuller.
1991Sumio Iijima uses electron microscopy to discover a type of cylindrical fullerene known as a
carbon nanotube, though earlier work had been done in the field as early as 1951. This material is an important component in the field of
nanotechnology.
1994First
total synthesis of Taxol by
Robert A. Holton and his group.
1995Eric Cornell and
Carl Wieman produce the first
Bose–Einstein condensate, a substance that displays quantum mechanical properties on the macroscopic scale.
