Chemistry

The 2026 Nobel Prize in Chemistry was awarded to Henri B. Kagan and Kenso Soai for discoveries on non-linear effects and autocatalysis in asymmetric organic synthesis.

Absorption is the uptake of a substance into the bulk of another material, often used to separate gases by dissolving them in liquids.

A chemical reaction involving proton transfer between an acid and a base, or electron-pair donation and acceptance under the broader Lewis definition.

Activation energy quantifies the temperature dependence of a reaction rate constant and is commonly interpreted as an energy barrier to chemical transformation.

An activity coefficient is a dimensionless factor that expresses how a component’s thermodynamic activity differs from its normalized concentration or mole fraction.

Adsorption is the accumulation of substances at an interface through physical interactions or chemical bonding, enabling separation, purification, and surface characterization.

An adsorption isotherm describes how the equilibrium amount adsorbed varies with pressure or concentration at a fixed temperature.

Swedish inventor and industrialist who developed dynamite and bequeathed most of his fortune to establish the Nobel Prizes.

Ammonia is a nitrogen–hydrogen compound essential to fertilizer production, industrial chemistry, and the nitrogen cycle.

Amount of substance is an SI base quantity measuring the number of specified elementary entities in a system, expressed in moles.

Analytical chemistry develops and applies methods for identifying substances, measuring their amounts, and establishing the reliability of chemical measurements.

French chemist whose quantitative experiments, oxygen theory, and reform of chemical nomenclature helped establish modern chemistry.

An exponential relationship describing how a chemical reaction’s rate constant depends on absolute temperature and activation energy.

Asymmetric catalysis uses catalysts to favor the formation of one stereoisomer, enabling selective synthesis of chiral compounds.

Asymmetric synthesis is a set of chemical methods that create a new element of chirality so that stereoisomers form in unequal amounts.

An atom is the smallest unit of a chemical element. It has a dense nucleus of protons and neutrons surrounded by electrons.

Atomic number is the number of protons in an atomic nucleus, defining an element’s identity and its position in the periodic table.

An atomic orbital is a one-electron wavefunction describing the spatial quantum state of an electron in an atom.

The Avogadro constant is the exact proportionality constant relating the number of specified entities to amount of substance, with a value of 6.02214076 × 10²³ per mole.

Bond order is a numerical description of the multiplicity or degree of bonding between two atoms, defined differently in structural and quantum-chemical models.

Brunauer–Emmett–Teller theory models multilayer gas adsorption and provides a widely used method for estimating the specific surface area of solids.

A solution that resists changes in pH by using a weak acid–base pair to consume small additions of acid or base.

Calorimetry measures heat exchanged during chemical reactions and physical processes, enabling determination of energy changes, heat capacities, and thermal transitions.

Carbon is the chemical element with atomic number 6, whose versatile bonding underlies organic chemistry, life, and many important materials.

Carbon dioxide is a molecular compound central to photosynthesis, the carbon cycle, industrial processes, and Earth’s greenhouse effect.

Catalysis is the acceleration of a chemical reaction by a substance regenerated during the reaction, without changing its overall thermodynamic equilibrium.

Cellulose is a glucose-based structural polymer that reinforces plant cell walls and supplies raw material for paper, textiles, and other products.

A chemical bond is an interaction that holds atoms or groups of atoms together in molecules, crystals, and other stable chemical structures.

A chemical element is a species of atoms defined by a shared number of protons, forming the basis of chemical classification and the periodic table.

A chemical equation symbolically represents a reaction, identifying its reactants and products and expressing their relative quantities through balanced coefficients.

Chemical equilibrium is a dynamic state in which opposing reactions balance, leaving the overall composition unchanged under fixed conditions.

Chemical kinetics studies reaction rates, their dependence on physical and chemical conditions, and the mechanisms through which reactions proceed.

A chemical reaction interconverts chemical species through changes in bonding or electronic structure, governed by conservation laws, thermodynamics, and reaction kinetics.

Chemistry is the natural science that studies the composition, structure and properties of substances, how they react and change, and the energy involved.

Chirality is the property of an object or molecular arrangement that cannot be superimposed on its mirror image, giving it a distinct handedness.

Chromatography separates mixture components through their different distributions or interactions between a stationary phase and a moving phase.

Click chemistry is a modular approach to molecular construction that uses reliable, selective reactions to join building blocks efficiently.

Combustion is an exothermic chemical process in which a fuel reacts with an oxidizer, releasing heat and often producing a flame.

Conservation of mass states that a closed system’s mass remains constant in classical physics and ordinary chemistry, with relativistic qualifications arising from mass–energy equivalence.

The study of metal–ligand complexes, their bonding, structures, reactions, and roles in biological systems and functional materials.

A coordination polymer is an extended compound whose repeating units are connected through coordination bonds in one, two, or three dimensions.

A covalent bond is a chemical bond involving shared electron density between atoms, responsible for the structure of molecules and many extended solids.

Diamond is a solid form of carbon with a rigid covalent lattice that gives it the highest hardness of any bulk natural material, and it is an insulator in pure form but becomes a semiconductor when impurities are added.

Distillation separates mixture components through vaporization and condensation, exploiting differences in their distribution between liquid and vapor phases.

Russian chemist who formulated the periodic law, developed an influential periodic table, and predicted properties of undiscovered elements.

A system of electrodes and electrolytes that enables electrical energy conversion, electrically driven chemical reactions, or electrochemical measurement.

Electrochemistry studies the relationships between electrical phenomena and chemical processes, including charge transfer, energy conversion, and reactions at electrode interfaces.

An electrode is a conducting component that connects an electrical circuit to an electrochemical medium, enabling charge transfer, measurement, or storage.

Electrolysis uses electrical energy to drive chemical reactions, enabling metal production, surface coating, chemical manufacture, and hydrogen generation.

A substance or medium that conducts electric current through mobile ions, including solutions, molten salts, and certain solids.

Electron configuration describes how electrons occupy orbitals in atoms, ions, and molecules, providing a framework for understanding chemical periodicity and electronic states.

Electron density describes the spatial distribution of electrons, expressed as their expected number per unit volume.

Electronegativity measures an atom’s ability to attract electrons in a chemical bond and helps explain bond polarity and periodic trends.

An enantiomer is one of two stereoisomers that are non-superposable mirror images of each other, with potentially different behavior in chiral environments.

An equilibrium constant specifies the relationship between reactant and product activities at chemical equilibrium for a defined reaction and temperature.

Ethanol is a two-carbon alcohol, C₂H₅OH, made by fermentation or industrial synthesis. It is used as a fuel, beverage ingredient, solvent, and chemical feedstock.

German chemist who developed ammonia synthesis, received the 1918 Chemistry Nobel Prize, and directed chemical-warfare research during World War I.

Glucose is a six-carbon simple sugar that serves as a major biological fuel and a building block of larger carbohydrates.

A glycosidic bond connects a sugar’s anomeric carbon to another group, determining the structure and properties of carbohydrates and many other biomolecules.

Graphite is a layered crystalline form of carbon whose conductivity, lubricity, and thermal resistance support numerous industrial applications.