Chemistry

Metallic hydrogen: properties, formation, and significance Metallic hydrogen An encyclopedic overview of metallic hydrogen — its nature, how it forms under extreme pressure, occurrence in giant planets, experimental efforts, predicted properties and possibl…

Metalloid (Semimetal): Elements with Intermediate Properties Metalloid A metalloid is an element with physical and chemical traits between metals and nonmetals. Metalloids often show semiconductor behavior and include silicon, boron, germanium, arseni…

Methamphetamine — overview, properties, medical use, risks and history Methamphetamine Methamphetamine is a powerful synthetic stimulant used legally in limited medical contexts and widely abused illicitly. This article explains its properties, forms, effects, histor…

Methane (CH4): properties, sources, uses, and environmental impact Methane Methane (CH4) is the simplest alkane and a primary component of natural gas. This article explains its structure, properties, natural and human sources, applications, atmospheric b…

Methanol: properties, production, uses and safety Methanol Methanol (CH3OH) is the simplest alcohol: a colorless, flammable liquid used as solvent, fuel and chemical feedstock. It is toxic by ingestion or inhalation and requires careful ha…

Methyl — the CH3 unit in organic chemistry and biology Methyl Overview of the methyl unit (CH3): chemical nature, common forms, reactivity, biological roles such as DNA methylation, industrial uses, and important safety notes.

Methyl benzoate Methyl benzoate is the methyl ester of benzoic acid, a colorless liquid with a floral odor used in fragrances, flavorings, organic synthesis and as a component of plant scents and…

Methyl iodide (iodomethane) Methyl iodide Methyl iodide (iodomethane, CH3I) is a volatile organoiodine compound used as a methylating reagent and formerly as a soil fumigant; it is reactive and requires careful handling du…

Methyl isocyanate: properties, uses, hazards, and history Methyl isocyanate Methyl isocyanate (CH3NCO) is a volatile, highly reactive organic compound used as an industrial intermediate; it is notable for its toxicity and its role in the 1984 Bhopal disast…

Miller–Urey experiment: laboratory synthesis of organic compounds under early-Earth conditions Miller–Urey experiment A classic 1950s laboratory investigation that simulated early-Earth conditions and produced amino acids and other organic molecules, informing hypotheses about the chemical origins…

Mineralization Mineralization is the process of forming or concentrating minerals, most often in rocks, ores, bones, teeth, and fossils. The term is used in geology, biology, medicine, and paleon…

Mineralocorticoid Mineralocorticoids are steroid hormones from the adrenal cortex that regulate sodium, potassium and fluid balance. Aldosterone is the principal mineralocorticoid with key roles in…

Mirex — persistent chlorinated insecticide and environmental contaminant Mirex Mirex is a highly chlorinated insecticide once used against ants and termites. It is persistent, lipophilic, bioaccumulative and toxic to wildlife; it was banned by regulators in t…

Mixture (chemistry) Mixture A mixture is a physical combination of two or more substances (elements or compounds) that retain their individual properties and can usually be separated by physical methods.

Molar concentration (molarity): definition, units, and applications Molar concentration Molar concentration (molarity) is the amount of substance in moles per unit volume of solution. This article explains the definition, units, measurement issues, history, uses, and…

Molar heat capacity: definition, units, measurement, and temperature dependence Molar heat capacity Overview of molar heat capacity: definition, SI units (J·mol⁻¹·K⁻¹), measurement methods (calorimetry, immersion), Cp vs Cv, and how values vary with temperature and conditions

Molar mass The mass of one mole of a substance (g·mol⁻¹). Explains definition, calculation from atomic masses, isotopic averages, uses in stoichiometry, and common distinctions.

Mole (unit) The mole is the SI base unit for amount of substance, defined by a fixed Avogadro constant. It links microscopic counts of atoms or molecules to laboratory-scale masses and molar q…

Molecular geometry: shapes, principles and significance Molecular geometry Summary of molecular geometry: how atoms are arranged in three dimensions, key models (VSEPR, hybridization), common shapes, methods of determination, and why geometry matters for…

Molecular orbital (MO) Molecular orbital An overview of molecular orbitals: definition, types, construction methods, historical development, applications in chemistry and materials, and key distinctions like HOMO–LUMO and…

Molecular symmetry: concepts, point groups, and chemical applications Molecular symmetry Overview of molecular symmetry: symmetry elements and operations, point and space groups, experimental determination, and applications in spectroscopy, orbital theory, and reactivi…

Molecular Vibrational Modes: Internal Atomic Oscillations and Bond Stretching Molecular vibrations Explore molecular vibrational modes: how bonded atoms oscillate, bond stretching and angle changes, common vibrational types, simple mass–spring models and diatomic examples like H…

Molecule: definition, structure, properties and uses Molecule An overview of molecules: what they are, how atoms bond to form them, their behavior in different states of matter, notation, history, and practical roles in chemistry and everyday…

Molybdenum Molybdenum (Mo, atomic number 42) is a silvery transition metal valued for high-temperature strength and corrosion resistance. It is used in steels, catalysts, electronics, and as…

Monocalcium phosphate Monocalcium phosphate (Ca(H2PO4)2) is an acidic, water‑soluble calcium phosphate used in fertilizers, baking powder (leavening), animal feed and some industrial products.

Monomer: definition, chemical types, polymerization and applications Monomer A monomer is a simple chemical unit—an atom or molecule—that can join with others to form polymers. This article explains types of monomers, how they react, common examples and the…

Monosaccharide Monosaccharides are the simplest carbohydrates: single sugar units that serve as metabolic fuels and as building blocks for larger saccharides.

Monosodium glutamate (MSG): properties, uses, safety, and history Monosodium glutamate Monosodium glutamate (MSG) is the sodium salt of glutamic acid used to enhance umami flavor. It occurs naturally in many foods, is widely used in cooking and industry, and is regul…

Monounsaturated fat (MUFA) Monounsaturated fat Monounsaturated fats are dietary fats with one carbon–carbon double bond. Found in nuts, olives, avocados and olive oil, they are associated with favorable effects on blood lipids…

Monsanto process — catalytic carbonylation of methanol to acetic acid Monsanto process Industrial catalytic method that converts methanol and carbon monoxide into acetic acid using a rhodium/iodide catalyst. Developed and commercialized in the 1960s; later largely su…

Moonshine: Illicit and Unaged Distilled Spirit Moonshine Moonshine is a clear, often unaged distilled spirit historically produced outside regulation. It includes illegal bootleg liquor, regional traditions, public‑health risks, and mode…

Mortar (masonry): materials, history, types, and uses Mortar (masonry) Mortar is the paste that binds masonry units. This entry explains composition, setting mechanisms, historic development, common types, uses in construction, and distinctions from c…

Moscovium (element 115) Moscovium Moscovium (Mc, Z=115) is a synthetic, highly radioactive superheavy element produced in particle accelerators; it has no stable isotopes and is studied for nuclear and relativistic…

Mothball: chemical repellent used to protect stored textiles Mothball Small, volatile pesticide spheres used to protect stored fabrics from moths and mold; composed historically of naphthalene or now often 1,4‑dichlorobenzene, with safety and environ…

Mutagen: agents and processes that change genetic material Mutagen Overview of mutagens — physical, chemical, and biological agents that alter genetic material, how they act, common examples, detection methods such as the Ames test, and their uses…

Names and Groupings for Sets of Chemical Elements Names for sets of chemical elements Overview of how elements are grouped on the periodic table, common family names (alkali, halogens, transition, lanthanides, etc.), characteristic properties, history, and practical…

Naphtha Naphtha is a group of light, flammable hydrocarbon mixtures from crude oil refining and gas processing. It is widely used as a petrochemical feedstock, gasoline blendstock, and sol…

Naphthalene: properties, uses, and health considerations Naphthalene Naphthalene is a volatile, white crystalline hydrocarbon (C10H8) used historically in mothballs and chemical manufacture. This article covers its properties, uses, hazards, and saf…

Natron: natural sodium carbonate mineral, composition, history, and uses Natron Natron is a naturally occurring mixture dominated by sodium carbonate decahydrate; historically important in cleaning, mummification and glassmaking and still relevant through its…

Natural Gas: Composition, Uses, Extraction, and Environmental Effects Natural gas Comprehensive overview of natural gas: what it is, how it is produced and transported, its uses in energy and industry, environmental impacts, and distinctions among types.

Neodymium Neodymium is a soft, silvery rare-earth metal (symbol Nd, atomic number 60) used in powerful permanent magnets, lasers, glass coloring, and advanced electronics. Its chemistry, use…

Neon: properties, production, and applications of the inert gas Neon Comprehensive overview of neon — the inert gas (Ne, atomic number 10): its key physical and chemical properties, industrial production by air separation, and applications from sign…

Neptunium: properties, history, and uses of element 93 Neptunium Neptunium is a silvery, radioactive actinide with atomic number 93. Discovered in 1940, it is the first transuranic element and appears as a by-product in nuclear reactors and rese…

Nerve agent An overview of nerve agents: toxic organophosphorus chemicals that disrupt the nervous system, historical development, symptoms and treatment, legal status, and long-term effects.

Neutralization (acid–base reactions and their applications) Neutralization Neutralization is the chemical reaction in which acids and bases react to form water and a salt. It underpins titration, pH control, antacid action, soil treatment and many industr…

Nichrome: nickel‑chromium alloy used for heating elements Nichrome Nichrome is a family of nickel‑chromium resistance alloys, commonly about 80% nickel and 20% chromium. Valued for high electrical resistivity, oxidation resistance and stability at…

Nickel — properties, history, uses, and health considerations Nickel Nickel (Ni) is a silvery transition metal, atomic number 28. This article explains its properties, occurrence, industrial uses, biological effects, and notable facts.

Nickel silver: composition, properties, history and common uses Nickel silver Nickel silver (or German silver) is a copper–nickel–zinc alloy that resembles silver. This article explains its makeup, properties, history, uses, safety notes and how it differs f…