| α-addition (alpha-addition) |
|
α- (β-, γ-) ray spectrometer |
| α (alpha), β (beta) |
| α-cleavage (alpha-cleavage) |
| α-decay (alpha-decay) |
| α-effect |
| α-elimination |
| α-expulsion in photochemistry |
| α-oxo carbenes |
| α-particle (alpha-particle) |
| A-factor |
' ' value |
| ab initio calculationssuperseded |
| abatement in atmospheric chemistry |
| abeo- |
| abiological |
| abiotic |
| abiotic transformation |
| absolute activation analysis |
absolute activity,  quantity |
| absolute configuration |
| absolute counting in radioanalytical chemistry |
| absolute electrode potential |
| absolute full energy peak efficiency |
absolute lethal concentration ( )quantity |
absolute lethal dose ( )quantity |
| absolute photopeak efficiency |
| absolute preconcentration in trace analysis |
absorbance,  quantity |
| absorbance matching in spectrochemical analysis |
| absorbed dose of a substance |
absorbed dose,  of radiation |
| absorbed electron coefficient
in in situ microanalysis |
| absorbed electrons in in situ microanalysis |
| absorber |
absorptance,  quantity |
| absorption |
| absorption coefficient |
| absorption coefficient in biology |
absorption cross-section,  quantity |
| absorption factor |
| absorption intensity |
| absorption line |
| absorption pathlength of a sample cell |
| absorption spectrum |
| absorptivity |
| abstraction |
| abstraction process in catalysis |
| abundance sensitivity in mass spectrometry |
| ac |
accelerating voltage (high voltage,  ) scan
in mass spectrometry |
acceleration,  quantity |
| acceleration energy in in situ microanalysis |
acceleration of free fall,  quantity |
| accelerator in solvent extraction |
acceptable daily intake ( ) (1993, 65, 2008)quantityreplaced |
acceptable daily intake ( ) (2004, 76, 1036)quantity |
acceptor number ( )quantity |
| accommodation coefficient |
| accretion in atmospheric chemistry |
| accuracy of a measuring instrument |
| accuracy of measurement |
| acenes |
| acetals |
| acetogenins |
| acetonides |
| acetylene black |
| acetylenes |
| acetylides |
| Acheson graphite |
| achiral |
| achirotopic |
| acid |
| acid anhydrides |
| acid-labile sulfur |
| acid–base indicator |
| acid–base titration |
| acid deposition in atmospheric chemistry |
| acidimetric titration |
| acidity |
| acidity constant |
| acidity function |
| acidosis |
| acid rain in atmospheric chemistry |
| acid thioanhydrides |
| aci-nitro compounds |
actinic flux  quantity |
| actinometer |
| action spectrum |
| activated adsorption process |
| activated carbon |
| activated charcoal |
| activated complex |
| activation |
| activation in electrochemical corrosion |
| activation in radiochemistry |
| activation analysis (nuclear) |
| activation cross-section |
| activation energy (Arrhenius activation energy)quantity |
| activation reaction |
| activator |
| active centre |
| active medium |
| active metal in electrochemical corrosion |
| active site in heterogeneous catalysis |
| active solid |
| active species |
| active state in electrochemical corrosion |
| active transport in biology |
| activity |
activity,  of a radioactive materialquantity |
activity (relative activity),  quantity |
activity coefficient,  ,  quantity |
| acute toxicity |
| acylals |
| acyl anions |
| acyl carbenes |
| acyl cations |
| acyl groups |
| acyl halides |
| acylium ions |
| acyloins |
| acyloxyl radicals |
| acyl radicals |
| acyl species |
| added hydrogen |
| addend |
| addition |
| addition reaction |
| additive |
| additive name |
| additivity of mass spectra |
| additivity principle |
| adduct |
| adduct ion in mass spectrometry |
| adhesional wetting |
| adiabatic |
| adiabatic electron transfer |
| adiabatic ionization in mass spectrometry |
| adiabatic lapse rate in atmospheric chemistry |
| adiabatic photoreaction |
| adiabatic transition-state theory |
| adiabatic treatments of reaction rates |
| adjacent re-entry model in polymer crystals |
| adjusted retention volume in chromatography |
| adjuvant |
| ADMR |
| adsorbate |
| adsorbent |
| adsorber |
| adsorption |
| adsorption capacity |
| adsorption chromatography |
| adsorption complex |
| adsorption current |
| adsorption hysteresis |
| adsorption indicator |
| adsorption isobar |
| adsorption isostere |
| adsorption isothermsuperseded |
| adsorption isotherm in chromatography |
| adsorptive |
| advancement |
| advection in atmospheric chemistry |
| adverse effect |
| aeration in atmospheric chemistry |
| aerobe |
| aerobic |
| aerobic conditions |
| aerogel |
| aeromete in atmospheric chemistry |
| aerometric measurement in atmospheric chemistry |
| aerosol |
| affinity chromatography |
affinity of reaction,  quantity |
| after mass analysis in mass spectrometry |
| ageing of precipitate |
| agglomerate in catalysis |
| agglomeration |
| agglutination |
| aggregate in catalysis |
| aging (ageing) of a polymer |
| aglycon (aglycone) |
| agonist |
| agostic |
| agranular carbon |
| air contaminant in atmospheric chemistry |
| air-lift bioreactor |
| air mass in atmospheric chemistry |
| air monitoring station in atmospheric chemistry |
| air pollutant |
| air pollution |
| air pollution index (air quality index) |
| air pollution survey in atmospheric chemistry |
| air quality characteristic
in atmospheric chemistry |
| air resource management in atmospheric chemistry |
| air sampling network in atmospheric chemistry |
| Aitken particles |
| albedo |
| albumin |
| alcoholates |
| alcohols |
| alcoholysis |
| aldaric acids |
| aldazines |
| aldehydes |
| aldimines |
| alditols |
| aldoketoses |
| aldonic acids |
| aldoses |
| aldoximes |
| alert levels in atmospheric chemistry |
| alicyclic compounds |
| aliphatic compounds |
| aliquot in analytical chemistry |
| alkalimetric titration |
| alkaloids |
| alkalosis |
| alkanes |
| alkanium ions |
| alkenes |
| alkoxides |
| alkoxyamines |
| alkylenes |
| alkyl groups |
| alkylideneamino carbenes |
| alkylideneaminoxyl radicals |
| alkylideneaminyl radicals |
| alkylidene groups |
| alkylidenes |
| alkylidynes |
| alkyl radicals |
| alkynes |
| allele |
| allenes |
| allo- in amino-acid nomenclature |
| allometric |
| allosteric enzymes |
| allostery |
| allotriomorphic transition |
| allotropes |
| allotropic transition |
| allylic groups |
| allylic intermediates |
| allylic substitution reaction |
| alternant |
| alternating copolymer |
| alternating copolymerization |
| alternating current |
| alternating voltage |
| altocumulus cloud in atmospheric chemistry |
| altostratus cloud in atmospheric chemistry |
| ambident |
| ambient air in atmospheric chemistry |
| ambient air quality in atmospheric chemistry |
| ambo |
| Ames/salmonella test |
| amic acids |
| amide hydrazones |
| amide oximes |
| amides |
| amidines |
| amidium ions |
| amidrazones |
| aminals |
| amine imides |
| amine imines |
| amine oxides |
| amines |
| amine ylides |
| aminimides |
| aminium ions |
| aminiumyl radical ions |
| amino-acid residue in a polypeptide |
| aminonitrenes |
| aminooxyl radicals |
| amino radicals |
| amino sugars |
| aminoxides |
| aminoxyl radicals |
| aminylenes |
| aminylium ions |
| aminyl oxides |
| aminyl radicals |
| ammonium compounds |
| ammonium imines |
| ammonium ylides |
| ammoniumyl radical ions |
| amorphous carbon |
amount concentration,  quantity |
amount fraction,  ( for gaseous mixtures)quantity |
amount of substance,  quantity |
| amount-of-substance concentration |
amount-of-substance fraction,  |
| ampereunit |
| amperometric detection method
in electrochemical analysis |
| amphipathic |
| amphiphilic |
| amphiprotic (solvent) |
| ampholytes |
| amphoteric |
| amplification reaction |
| amplitude of alternating current |
| amplitude of alternating voltage |
| AM (0) sunlight |
| AM (1) sunlight |
| anabolism |
| anaerobe |
| anaerobic |
| anaesthetic |
| analgesic |
| analogue metabolism |
| analogue to digital converter (pulse) |
| analyte |
| analytical function |
| analytical instrument |
| analytical intercomparison |
| analytical portion |
| analytical pyrolysis |
| analytical quality control |
| analytical radiochemistry |
| analytical sample |
| analytical solution |
| analytical solution calorimetry |
| analytical unit (analyser) |
| anation |
| anchimeric assistance |
| aneroid barometer |
| Anger camera |
| anglequantity |
| angle of observation |
angle of optical rotation,  quantity |
| angle strain |
|
ångström
unit |
| angular distribution |
angular frequency,  quantity |
angular momentum,  quantity |
| anhydrides |
| anhydro bases |
| anilides |
| anils |
| anion |
| anion exchange |
| anion exchanger |
| anionic polymerization |
| anionotropic rearrangement (or anionotropy) |
| anion radical |
| anisometric |
| anisotropy |
| annelation |
| annihilation |
| annulation |
| annulenes |
| annulenylidenes |
| anode |
| anodic transfer coefficient |
| anomeric effect |
| anomers |
| ansa compounds |
| antagonism |
| antagonist |
| antarafacial |
| anthelmint(h)ic |
| anthocyanidins |
| anthocyanins |
| anti |
| antiaromatic compounds |
| antibiotic |
| antibody |
| anticholinergic |
| anticircular elution (anticircular development)
in planar chromatography |
| anticlinal |
| anticlined structures in polymers |
| anticodon |
| anti-Compton γ-ray spectrometer |
| anticyclone in atmospheric chemistry |
| antiferroelectric transition |
| antiferromagnetic transition |
| antigen |
| anti-Hammond effect |
| antihelminth |
| anti-Markownikoff addition |
| antimetabolite |
| antimony–xenon lamp (arc) |
| antimycotic |
| antiparticle |
| antiperiplanar |
| antipodes |
| antiprismo- |
| antiresistant |
| antiserum |
| anti-Stokes shift |
| anti-Stokes type radiation (fluorescence) |
| anti-thixotropy |
| ap |
| apex |
| apex current |
| apex potential |
| aphicide |
| apical (basal, equatorial) |
| apo- in carotenoid nomenclature |
| apoenzyme |
| apoprotein |
| apoptosis |
| apparent (quantity) |
| apparent lifetime |
| apparent viscosity of a liquid |
| appearance energy (appearance potential) |
| appearance potential |
appearance temperature,
in electrothermal atomization |
| applied potential |
| aprotic (solvent) |
| aquation |
| arachno- |
| Archibald's method |
| area of an electrode-solution interface |
| area of interface |
| area viscosity |
| areic |
| arene epoxides |
| arene oxides |
| arenes |
| arenium ions |
| arenols |
| arenonium ions |
| argon ion laser |
| arithmetic mean (average) |
| aromatic |
| aromaticity |
| arrester in atmospheric chemistry |
Arrhenius  factor |
| Arrhenius energy of activation |
| Arrhenius equation |
| arsanes |
| arsanylidenes |
| arsanylium ions |
| arsenides |
| arsine oxides |
| arsines |
| arsinic acids |
| arsinidenes |
| arsinous acids |
| arsonic acids |
| arsonium compounds |
| arsonous acids |
| arsoranes |
| artificial graphite |
| artificial neural networks |
| artificial radioactivity |
| aryl cations |
| arylene groups |
| aryl groups |
| aryne |
| ascending elution (ascending development)
in planar
chromatography |
| ash in atmospheric chemistry |
| ashing in analysis |
| aspirator |
| assay |
| assay kit |
| association |
| association reaction (associative combination)
in mass
spectrometry |
| associative desorption |
| associative ionization in mass spectrometry |
| associative surface reaction |
| asym- |
| asymmetric |
| asymmetric carbon atom |
| asymmetric centre |
| asymmetric destruction |
| asymmetric film |
| asymmetric induction |
| asymmetric membrane |
| asymmetric synthesis |
| asymmetric transformation |
| asymmetry |
| asymmetry potential of a glass electrode |
| atactic macromolecule |
| atactic polymer |
| atmosphereunit |
| atmosphere of the earth |
| atmospheric pressure ionization
in mass spectrometry |
| atom |
| atomic fluorescence |
| atomic laser |
atomic mass  quantity |
| atomic mass constantconstant |
| atomic mass unit |
atomic number (proton number),  quantity |
atomic orbital,  ,  ,  |
| atomic ring-sector |
| atomic spectral lines |
| atomic symbol |
| atomic units |
| atomic weight |
| atomization in analytical flame spectroscopy |
atomization surface temperature, 
in electrothermal atomization |
| atomize |
| atomizer in analytical flame spectroscopy |
| atom–molecule complex mechanism |
| atropisomers |
| attachment |
attenuance,  quantity |
| attenuance filter |
| attenuation |
| attenuation coefficient |
| attoSI unit prefix |
| attractive–mixed–repulsive
(AMR) classification |
| attractive potential-energy surface |
| attributable risk |
| Auger effect |
| Auger electron |
| Auger electron spectroscopy |
| Auger electron yield |
| Auger yield |
| autacoid |
| autocatalytic reaction |
| auto-ionization in mass spectrometry |
| automation in analysis |
| automerization |
| autophobicity |
| autopoisoning in catalysis |
| autoprotolysis |
| autoprotolysis constant |
| autoradiograph |
| autoradiolysis |
| auxiliary electrode |
| auxochrome |
| auxotrophy |
| avalanche photodiode |
| average current density |
| average degree of polymerization |
| average life in nuclear chemistry |
| average rate of flow in polarography |
| Avogadro constantconstant |
| avoided crossing of potential-energy surfaces |
| Avrami equation |
| axial (equatorial) |
| axial chirality |
| axialite in polymer crystals |
| axis of chirality |
| axis of helicity |
| azacarbenes |
| azamines |
| azanes |
| azenes |
| azides |
| azimines |
| azines |
| azinic acids |
| azlactones |
| azo compounds |
| azo imides |
| azomethine imides |
| azomethine oxides |
| azomethines |
| azomethine ylides |
| azonic acids |
| azoxy compounds |
| azo ylides |
| azylenes |
