Chemistry Abbreviations
106 abbreviations · part of Science & Engineering Abbreviations
Abbreviations used in chemistry laboratories, journals, safety documents and industry: analytical techniques such as NMR, HPLC and GC-MS, standard conditions and concentration notation, common solvents and reagents, plastics and polymers, and well-known compounds and pollutants. Nomenclature and symbols are standardized by IUPAC, while shorthand such as THF, DMSO or EtOAc is a long-standing convention of the laboratory. Element symbols such as Na or Fe have their own list.
| Abbreviation | Stands for | Description |
|---|---|---|
| AAS | Atomic absorption spectroscopy | Method for measuring individual metals by atomizing a sample in a flame or graphite furnace and measuring how much light from an element-specific lamp the free atoms… |
| ABS | Acrylonitrile butadiene styrene | Tough, impact-resistant thermoplastic combining three monomers: acrylonitrile for chemical resistance, butadiene for toughness and styrene for rigidity and gloss. |
| Ac | Acetyl group | Organic abbreviation for the acetyl group, CH3CO-, found in shorthand such as AcOH (acetic acid), Ac2O (acetic anhydride) and OAc (acetate). |
| aq | Aqueous | State symbol written after a formula to show that a substance is dissolved in water, as in NaCl(aq). |
| BPA | Bisphenol A | Industrial chemical used to make polycarbonate plastics and the epoxy resins that line many food and drink cans. |
| CAS | Chemical Abstracts Service | Division of the American Chemical Society that maintains the CAS Registry, the largest database of chemical substances. |
| CFC | Chlorofluorocarbon | Compound containing only carbon, chlorine and fluorine, once used widely as refrigerants, aerosol propellants and foam-blowing agents under trade names such as Freon. |
| CH4 | Methane | Simplest hydrocarbon, one carbon bonded to four hydrogens, and the main component of natural gas. |
| CO | Carbon monoxide | Colorless, odorless, toxic gas formed by incomplete combustion in furnaces, generators, vehicles and charcoal grills. |
| CO2 | Carbon dioxide | Colorless gas produced when carbon-containing fuels burn and when organisms respire, and absorbed by plants during photosynthesis. |
| conc. | Concentrated | Label for reagents supplied at full commercial strength, especially acids: conc. sulfuric acid is about 96-98% H2SO4, conc. hydrochloric acid about 37% HCl and conc.… |
| DCM | Dichloromethane | Volatile chlorinated solvent, CH2Cl2, used for extractions, chromatography and paint stripping, and formerly to decaffeinate coffee. |
| DDT | Dichlorodiphenyltrichloroethane | Synthetic insecticide used massively from the 1940s to control mosquitoes, lice and crop pests, helping eliminate malaria from many regions. |
| DFT | Density functional theory | Quantum mechanical method that calculates the electronic structure of molecules and solids from the electron density rather than from the full many-electron wavefunction. |
| DI | Deionized (water) | Water purified by passing it through ion-exchange resins that remove dissolved mineral ions such as calcium, sodium and chloride. |
| DMF | Dimethylformamide | High-boiling polar aprotic solvent, HCON(CH3)2, used in peptide synthesis, coupling reactions, acrylic fiber spinning and coatings. |
| DMSO | Dimethyl sulfoxide | Colorless polar aprotic solvent, (CH3)2SO, that dissolves an unusually wide range of polar and nonpolar substances and mixes with water. |
| DSC | Differential scanning calorimetry | Thermal analysis method that measures the heat flowing into or out of a sample, compared with a reference, as both are heated or cooled. |
| EDTA | Ethylenediaminetetraacetic acid | Chelating agent that wraps around metal ions such as calcium, magnesium, iron and lead, holding them tightly in solution. |
| EPR | Electron paramagnetic resonance | Spectroscopy that detects unpaired electrons by placing a sample in a magnetic field and measuring microwave absorption. |
| EPS | Expanded polystyrene | Lightweight foam made by expanding polystyrene beads with steam and fusing them in a mold, leaving a material that is about 95-98% air. |
| equiv | Equivalent(s) | Unit used in synthetic procedures to express the amount of a reagent relative to the limiting starting material, in moles. |
| ESI | Electrospray ionization | Ionization technique that sprays a liquid through a charged needle, producing fine droplets that evaporate and leave gas-phase ions, often carrying multiple charges. |
| Et | Ethyl group | Abbreviation for the ethyl group, -CH2CH3, a two-carbon fragment derived from ethane. |
| EtOAc | Ethyl acetate | Sweet-smelling ester, CH3COOC2H5, used as a moderately polar solvent for extractions and column chromatography, often mixed with hexanes. |
| ETOH | Ethanol (alcohol) | Shorthand for alcohol in social histories, toxicology results and assessments, as in "ETOH use", "ETOH withdrawal" or "ETOH level". |
| EVA | Ethylene-vinyl acetate | Soft, rubbery copolymer used for shoe midsoles, flip-flops, yoga mats, craft foam sheets, hot-melt glue sticks and the encapsulant that bonds solar cells inside panels. |
| FTIR | Fourier-transform infrared spectroscopy | The standard modern form of infrared spectroscopy, in which an interferometer collects all wavelengths at once and a Fourier transform converts the signal into a… |
| GC | Gas chromatography | Separation technique in which a vaporized sample is carried by an inert gas, usually helium, hydrogen or nitrogen, through a long thin column inside an oven. |
| GC-MS | Gas chromatography-mass spectrometry | Combination of a gas chromatograph, which separates a mixture, with a mass spectrometer, which identifies each separated compound by its fragmentation pattern. |
| GHS | Globally Harmonized System of Classification and Labelling of Chemicals | United Nations framework that standardizes how chemical hazards are classified and communicated on labels and safety data sheets. |
| H2O | Water | Chemical formula of water: two hydrogen atoms bonded to one oxygen at an angle of about 104.5 degrees. |
| H2O2 | Hydrogen peroxide | Pale blue liquid in pure form, sold in brown bottles as a 3% solution for cleaning cuts and disinfecting surfaces, and at higher strengths for hair bleaching, pulp and… |
| H2SO4 | Sulfuric acid | Dense, oily, strongly acidic liquid produced in larger quantities than any other industrial chemical, so its output has long served as an indicator of industrial… |
| HCFC | Hydrochlorofluorocarbon | Transitional replacement for CFCs in which some halogen atoms are swapped for hydrogen, so the molecule breaks down partly in the lower atmosphere and does less damage… |
| HCl | Hydrochloric acid | Strong acid formed by dissolving hydrogen chloride gas in water. |
| HDPE | High-density polyethylene | Stiff, opaque polyethylene with little chain branching, used for milk jugs, detergent bottles, cutting boards, gas and water pipes and outdoor lumber. |
| HFC | Hydrofluorocarbon | Refrigerant and propellant containing hydrogen, fluorine and carbon but no chlorine, adopted to replace CFCs and HCFCs because it does not harm the ozone layer. |
| HOMO | Highest occupied molecular orbital | The highest-energy molecular orbital that contains electrons. |
| HPLC | High-performance liquid chromatography | Analytical method that pumps a liquid sample at high pressure through a column packed with fine particles, separating its components by how strongly they interact with… |
| ICP-MS | Inductively coupled plasma mass spectrometry | Ultrasensitive technique that sprays a dissolved sample into an argon plasma hotter than 6,000 kelvins, converting elements into ions that a mass spectrometer counts. |
| IPA | Isopropyl alcohol | Common name for 2-propanol, (CH3)2CHOH, the main ingredient of rubbing alcohol and a widely used cleaning solvent. |
| IR | Infrared spectroscopy | In chemistry reports IR usually means infrared spectroscopy, which measures which infrared wavelengths a sample absorbs. |
| IUPAC | International Union of Pure and Applied Chemistry | World authority on chemical nomenclature, symbols, terminology and atomic weights, founded in 1919. |
| LC-MS | Liquid chromatography-mass spectrometry | Analytical pairing of liquid chromatography with mass spectrometry, used for compounds that are too large, polar or heat-sensitive for gas chromatography, such as… |
| LD50 | Lethal dose, 50% | Dose of a substance that kills half of a group of test animals, usually expressed in milligrams per kilogram of body weight. |
| LDPE | Low-density polyethylene | Soft, flexible polyethylene with many branched chains, used for plastic films, grocery and bread bags, squeeze bottles, shrink wrap and the coating on milk cartons. |
| LUMO | Lowest unoccupied molecular orbital | The lowest-energy molecular orbital that holds no electrons, the first place an added or excited electron goes. |
| M | Molar (moles per liter) | Unit of concentration equal to one mole of solute per liter of solution, written as a capital M after a number, such as 0.1 M HCl. |
| MALDI | Matrix-assisted laser desorption/ionization | Gentle ionization method for mass spectrometry in which a sample is mixed with a light-absorbing matrix and hit with laser pulses, lifting large molecules such as… |
| Me | Methyl group | Organic chemistry symbol for the methyl group, -CH3, a carbon bonded to three hydrogens. |
| MEK | Methyl ethyl ketone | Fast-evaporating solvent, also called butanone, CH3COCH2CH3, used in paints, adhesives, printing inks and as a cleaner for plastics and metal parts. |
| MeOH | Methanol | Shorthand for methanol, CH3OH, the simplest alcohol, used as a solvent, antifreeze, fuel and feedstock for formaldehyde and acetic acid. |
| MOF | Metal-organic framework | Crystalline material built from metal ions or clusters linked by organic molecules into a porous, cage-like network with enormous internal surface area; a few grams can… |
| MS | Mass spectrometry | Technique that converts molecules into ions and sorts them by mass-to-charge ratio, giving a molecule's mass and, from its fragments, clues to its structure. |
| MSDS | Material safety data sheet | Older name and format for the document describing a chemical product's hazards, safe handling and emergency measures. |
| MSG | Monosodium glutamate | Flavor enhancer that delivers umami, the savory taste of broths, aged cheese and ripe tomatoes. |
| MTBE | Methyl tert-butyl ether | Ether, (CH3)3COCH3, once blended into US gasoline as an oxygenate to raise octane and cut carbon monoxide emissions. |
| MW | Molecular weight | Mass of a molecule relative to one twelfth of a carbon-12 atom, numerically equal to the molar mass in grams per mole. |
| N2O | Nitrous oxide | Sweet-smelling gas known as laughing gas, used as a mild anesthetic in dentistry and childbirth, as the propellant in whipped-cream chargers and as a power booster in… |
| NaCl | Sodium chloride | Formula of table salt, an ionic compound of sodium and chloride ions arranged in a cubic crystal lattice. |
| NaOH | Sodium hydroxide | Strong base, also called lye or caustic soda, sold as white pellets or flakes and as concentrated solution. |
| NH3 | Ammonia | Blood ammonia, a nitrogen waste product normally converted to urea by the liver, is measured when hepatic encephalopathy, a urea cycle disorder, Reye syndrome or… |
| NMR | Nuclear magnetic resonance | Spectroscopic technique that places a sample in a strong magnetic field and probes atomic nuclei such as hydrogen-1 and carbon-13 with radio waves. |
| NTP | Normal temperature and pressure | Gas reference conditions of 20 °C (293.15 K) and 1 atmosphere (101.325 kPa), common in the United States for rating compressors, gas flow and air quality. |
| O3 | Ozone | Pale blue gas made of three oxygen atoms. |
| PAH | Polycyclic aromatic hydrocarbon | Compound made of two or more fused benzene rings, such as naphthalene, anthracene and benzo[a]pyrene. |
| PC | Polycarbonate | Clear, extremely impact-resistant thermoplastic used for eyeglass and safety lenses, bullet-resistant glazing, greenhouse panels, helmets, phone cases and electronics… |
| PCB | Polychlorinated biphenyl | Synthetic chlorinated compound once used as insulating fluid in transformers and capacitors and in caulk, paints and hydraulic fluids, because it resists fire and… |
| PE | Polyethylene | The most produced plastic in the world, a chain of repeating ethylene units used for shopping bags, packaging films, bottles, pipes and toys. |
| PEG | Polyethylene glycol (laxative and bowel preparation) | Osmotic agent that draws water into the bowel; in small daily doses it treats constipation, and in large-volume electrolyte solutions it cleanses the colon before… |
| PET | Polyethylene terephthalate | Clear, strong polyester used for most soft-drink and water bottles, food trays and synthetic fibers, where it is simply called polyester. |
| PFAS | Per- and polyfluoroalkyl substances | Large class of thousands of synthetic chemicals built on chains of carbon-fluorine bonds, among the strongest in chemistry. |
| PFOA | Perfluorooctanoic acid | Eight-carbon PFAS chemical formerly used to manufacture PTFE (Teflon) and other fluoropolymers. |
| PFOS | Perfluorooctanesulfonic acid | PFAS chemical once central to Scotchgard-type stain repellents and to firefighting foams used at airports and military bases. |
| pH | Potential of hydrogen | Scale from about 0 to 14 that expresses how acidic or basic a water solution is, defined as the negative logarithm of hydrogen-ion activity. |
| pKa | Acid dissociation constant (negative logarithm) | Measure of acid strength: the negative base-10 logarithm of the acid dissociation constant, Ka. |
| PLA | Polylactic acid | Bio-based, compostable polyester made from fermented plant sugars, typically from corn or sugarcane. |
| PMMA | Poly(methyl methacrylate) | Transparent, shatter-resistant plastic sold as acrylic glass or under brand names such as Plexiglas, Perspex and Lucite. |
| PP | Polypropylene | Tough, heat-resistant plastic used for yogurt and takeout containers, bottle caps, car bumpers, syringes, carpet fibers and the melt-blown filter layer of face masks. |
| ppt | Precipitate | Lab-notebook shorthand for a solid that forms and settles out of solution during a reaction, such as the white silver chloride produced when silver nitrate meets a… |
| PS | Polystyrene | Plastic made from styrene, produced as rigid clear polystyrene for disposable cutlery, CD cases and laboratory dishes, and as lightweight foam for cups, packaging and… |
| PTFE | Polytetrafluoroethylene | Fluoropolymer famous for its slipperiness and chemical resistance, best known by the brand name Teflon. |
| PU | Polyurethane | Large family of polymers made by reacting isocyanates with polyols, ranging from flexible foam in mattresses and car seats to rigid insulation and spray foam… |
| PVA | Polyvinyl alcohol | Water-soluble synthetic polymer used for the dissolving film around laundry and dishwasher pods, paper coatings, textile sizing and soluble support material in 3D… |
| PVC | Polyvinyl chloride | The world's third most produced synthetic plastic, after polyethylene and polypropylene. |
| Rf | Retention factor | In thin-layer and paper chromatography, the distance a compound travels divided by the distance the solvent front travels, a number between 0 and 1. |
| RT | Room temperature | Laboratory shorthand for ordinary ambient temperature, usually about 20-25 °C, written in procedures where no heating or cooling is applied. |
| RTP | Room temperature and pressure | Informal reference conditions, usually 20 or 25 °C and 1 atmosphere, used in school chemistry for gas calculations. |
| SATP | Standard ambient temperature and pressure | IUPAC reference conditions of 25 °C (298.15 K) and 100 kPa, used for tabulating thermodynamic data such as standard enthalpies of formation. |
| SDS | Safety data sheet | Standardized document that suppliers must provide with hazardous chemicals, describing hazards, safe handling, first aid, firefighting, storage and exposure limits in… |
| SLS | Sodium lauryl sulfate | Inexpensive surfactant that makes toothpaste, shampoo, body wash and dish soap foam. |
| SN1 | Unimolecular nucleophilic substitution | Two-step organic reaction mechanism in which a leaving group departs first to form a carbocation, which a nucleophile then attacks. |
| SN2 | Bimolecular nucleophilic substitution | One-step organic reaction in which a nucleophile attacks a carbon from the side opposite the leaving group, flipping the stereocenter like an umbrella in the wind. |
| STP | Standard temperature and pressure | Reference conditions for reporting gas volumes and properties. |
| TFA | Trifluoroacetic acid | Strong, volatile organic acid, CF3COOH, widely used to remove Boc protecting groups and to cleave peptides from resin in solid-phase synthesis. |
| TGA | Thermogravimetric analysis | Technique that continuously weighs a sample as it is heated, revealing temperatures at which it loses water, decomposes or oxidizes. |
| THF | Tetrahydrofuran | Cyclic ether, C4H8O, widely used as a reaction solvent, especially for Grignard and organolithium chemistry, and industrially as a precursor to spandex fibers and a… |
| TLC | Thin-layer chromatography | Quick, inexpensive separation method in which a spot of sample on a plate coated with silica gel is developed with a solvent that creeps up the plate by capillary action. |
| TMS | Tetramethylsilane | Volatile, inert liquid, Si(CH3)4, added in small amounts to NMR samples as the zero point of the chemical-shift scale. |
| TNT | Trinitrotoluene | Yellow solid explosive, C7H5N3O6, prized because it is relatively insensitive to shock and can be melted and poured safely into shells. |
| UV-Vis | Ultraviolet-visible spectroscopy | Measurement of how much ultraviolet and visible light, roughly 190 to 800 nanometers, a solution absorbs. |
| VOC | Volatile organic compound | Carbon-based chemical that evaporates readily at room temperature, such as benzene, formaldehyde, toluene and the solvents in paints, cleaners and fuels. |
| VSEPR | Valence shell electron pair repulsion | Model that predicts molecular shapes from the idea that electron pairs around a central atom repel one another and spread as far apart as possible. |
| XRD | X-ray diffraction | Technique that directs X-rays at a crystalline material and records the angles at which they are diffracted, revealing the arrangement of atoms. |
| XRF | X-ray fluorescence | Non-destructive way to find which elements a material contains by exciting it with X-rays and measuring the characteristic secondary X-rays each element emits. |
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