observation height,
in flame emission and absorption spectrometry |
observation pathlength,
in flame emission and absorption spectrometry |
| observation space
in flame emission and absorption spectrometry |
observation volume,
in flame emission and absorption spectrometry |
| observed rate coefficient |
| occlusion (molecular) |
| octahedro- in inorganic nomenclature |
| odd-electron ion |
| ODMR (Optically Detected Magnetic Resonance) |
| odour threshold in atmospheric chemistry |
|
ohm
unit |
| olefins |
| oligo |
| oligomer |
| oligomeric |
| oligomerization |
| oligomer molecule |
| oligonucleotides |
| oligopeptides |
| oligosaccharides |
| one-colour indicator |
| onium compounds |
| open atomizer |
| open dynamic system in spectrochemical analysis |
| open film |
| open hearth furnace in atmospheric chemistry |
| open static system in spectrochemical analysis |
| open-tubular column in chromatography |
| operational pH cell |
| operational pH standard |
| operator gene |
| operon |
| opposing reactions |
| optical activity |
| optical antipodes |
| optical-beam error in spectrochemical analysis |
| optical density |
| optical filter |
| optical isomers |
| optically labile |
| optical purity |
| optical resolution |
| optical rotation |
| optical rotatory power |
| optical spectroscopy |
| optical yield |
| optoacoustic spectroscopy |
| orbital |
| orbital energy |
| orbital steering |
| orbital symmetry |
| order-disorder transition |
order of reaction,
quantity |
| order parameter |
| organelles |
| organic dye laser |
| organo- |
| organoheteryl groups |
| organometallic compounds |
| organyl groups |
| origin of replication (ori) |
| ortho acids |
| ortho amides |
| ortho- and peri-fused (polycyclic compounds) |
| ortho esters |
| ortho-fused (polycyclic compounds) |
| orthokinetic aggregation in colloids |
| osazones |
| oscillating reaction |
oscillator strength,
|
osmolality,  quantity |
| osmolarity |
osmotic coefficient,
quantity |
osmotic concentration,  quantity |
osmotic pressure,
quantity |
| osones |
| osotriazoles |
| Ostwald ripening |
outer electric potential,
quantity |
| outer Helmholtz plane (OHP) |
| outer-sphere electron transfer |
| outgassing of a catalyst |
| out-isomer |
| out-of-plane bending coordinate
in molecular geometry |
| output rate |
| overall activation energy |
overlap integral,
|
overpotential,
quantity |
| oxa-di-π-methane rearrangement |
| oxenium ions |
| oxidant in atmospheric chemistry |
| oxidation |
| oxidation number |
| oxidation–reduction (redox) titration |
| oxidation state |
| oxidative addition |
| oxidative coupling |
| oxidized species |
| oxidoreductases |
| oxime O-ethers |
| oximes |
| oxo acids |
| oxoacids |
| oxocarbons |
| oxo carboxylic acids |
| oxo compounds |
| oxonium ions |
| oxonium ylides |
| oxyacid (oxy-acid) |
| oxygen-flask combustion
in spectrochemical analysis |
| oxylium ions |
| ozone hole |
| ozonides |
