| π – π* state |
| π → π* transition |
| π → σ* transition |
| π-adduct |
| π-bond |
| π-complex |
| π-electron acceptor/donor group |
|
P, M
|
| packed column in chromatography |
| packing in column chromatography |
| paddlanes |
| pair attenuation coefficient in nuclear chemistry |
pair correlation length,
in thin filmsquantity |
| pair production in nuclear chemistry |
| Pallmann effect |
| PAN-based carbon fibres |
| paraffin |
| parallel-chain crystal in polymers |
| parallel reactions |
| paramagnetic |
| parent hydride |
| parent ion in mass spectrometry |
| partial anodic (cathodic) current |
| partial charge exchange reaction |
| partial charge transfer reaction |
| partial decay constant in nuclear chemistry |
| partial digestion in spectrochemical analysis |
| partial isotherm (or individual isotherm)
in surface chemistry |
| partial kinetic current in electrochemistry |
| partial least squares (PLS) |
| partially draining |
partial mass density,
quantity |
| partial microscopic diffusion control (encounter
control)
|
| partial molar Gibbs energy |
| partial molar quantity |
| partial order of reaction |
| partial pressure |
| partial rate factor |
partial specific volume,
|
| particle concentration in atmospheric chemistry |
| particle density in nuclear chemistry |
| particle induced X-ray emission analysis |
| particle scattering factor |
| particle scattering function |
| particle size in atmospheric chemistry |
| particle size distribution
in atmospheric chemistry |
| particular property |
| particulate carbon |
| particulate matter in atmospheric chemistry |
| partition |
| partition chromatography |
| partition coefficient |
partition constant,
quantity |
| partition function |
| partition isotherm in chromatography |
partition ratio,
quantity |
| partly open film |
|
pascal
unit |
| passivation in electrochemical corrosion |
| passivation potential in electrochemical corrosion |
| passive metal |
| passive sampler |
| passive state in electrochemical corrosion |
| Paterno–Büchi reaction |
| pattern recognition |
| paucidisperse system |
| PDMR |
| peak in chromatography |
| peak analysis |
| peak area in chromatography |
| peak area method |
| peak base in chromatography |
| peak concentration (trace atmospheric component) |
| peak current |
peak elution volume (time),
 ,
in column chromatography |
| peak enthalpimetry |
| peak fitting |
| peak height in chromatography |
| peak maximum in chromatography |
| peak potential |
peak resolution,
in chromatographyquantity |
| peak widths in chromatography |
| pectins |
| Peierls transition |
| pellicular packing in chromatography |
| penams |
| pendant chain |
| pendant group (side group) |
| penems |
| penetrant (permeant) |
| penetration depth |
| penicillins |
| Penning gas mixture |
| pentads in polymers |
| pentaprismo- |
| peptides |
| peptidoglycan |
| peptization in colloid chemistry |
| per acids |
| percent |
| percentage error |
| percentage exposed in metallic catalysts |
percentage relative error,
(%)
|
percentage standard deviation,
 (%),
 (%)
|
| percent diastereoisomer excess |
| percent enantiomer excess |
| perfectly polarized interphase |
| perfusion stationary phase (material) in liquid chromatography |
| pericyclic reaction |
| perikinetic aggregation in colloids |
period,
quantity |
| periodic copolymer |
| periodic copolymerization |
| periodic voltage |
| peripheral atom in organic reaction mechanisms |
| periplanar |
| periselectivity |
| peritectic reaction |
| peritectoid reaction |
| peritectoid temperature |
permeability,
quantity |
permeability of vacuum,
constant |
| permeate |
| permeation chromatography |
| permeation tube |
permittivity,
quantity |
| permittivity of vacuumconstant |
| permselectivity |
| peroxides |
| peroxisome |
| peroxo compounds |
| peroxy acids |
| perpendicular effect |
| persistence length in polymers |
| persistent |
| perspective formula |
| perstraction |
| perturbed dimensions in polymers |
| pervaporation |
| pesticide |
| pesticide residue |
| petaSI unit prefix |
| petroleum coke |
| petroleum pitch |
| pH |
| pH0.5 or pH1/2 in solvent extraction |
| pharmacodynamics |
| pharmacokinetics (2004, 76, 1064) |
| pharmacokinetics (1993, 65, 2082)replaced |
| phase |
| phase fluorimetry |
| phase I reaction of biotransformation |
| phase II reaction of biotransformation |
| phase inversion |
phase ratio,
in chromatographyquantity |
phase ratio,
in liquid-liquid distributionquantity |
| phase rule |
| phase separation |
| phase-space theory |
| phase-transfer catalysis |
| phase transition |
| phenolates |
| phenols |
| phenomenological equation |
| phenonium ions |
| phenotype |
| phenoxides |
| pheromone |
| pH glass electrode |
| pH gradient in electrophoresis |
| phonon |
| phosphanes |
| phosphanylidenes |
| phosphatidic acids |
| phosphazenes |
| phosphine oxides |
| phosphines |
| phosphinic acids |
| phosphinidenes |
| phosphinous acids |
| phospho |
| phosphoglycerides |
| phospholipids |
| phosphonic acids |
| phosphonitriles |
| phosphonium compounds |
| phosphonium ylides |
| phosphono |
| phosphonous acids |
| phosphoramides |
| phosphoranes |
| phosphoranyl radicals |
| phosphorescence |
| phosphorimetry |
| phosphoroscope |
| phosphorus ylides |
| phosphorylation |
| phosphylenes |
| photoacoustic detector |
| photoacoustic effect |
| photoacoustic spectroscopy |
| photoadsorption |
| photoaffinity labelling |
| photoassisted catalysis |
| photocatalysis |
| photocatalytic cell |
| photochemical detector |
| photochemical equivalence |
| photochemical hole burning |
| photochemical reaction |
| photochemical smog |
| photochemical yield |
| photochemistry |
| photochromism |
| photoconductive detector |
| photoconductivity |
| photocrosslinking |
| photocuring |
| photocurrent yield |
| photodegradation |
| photodesorption |
| photodetachment of electrons |
| photodiode |
| photodiode array |
| photodynamic effect |
| photoelectrical effect |
| photoelectric attenuation coefficient |
| photoelectric detector |
| photoelectric peak |
| photoelectrochemical cell |
| photoelectrochemical etching |
| photoelectrochemistry |
| photoelectrolytic cell |
| photoelectron spectroscopy (PES) |
| photoelectron yield |
| photoemissive detector |
| photoexcitation |
| photo-Fries rearrangement |
| photogalvanic cell |
| photoimaging |
| photoinduced electron transfer |
| photoinduced polymerization |
| photoinitiation |
| photoionization |
| photoionization detector in gas chromatography |
| photoisomerization |
| photoluminescence |
| photolysis |
| photometry |
| photomultiplier tube |
| photon |
| photon activation |
| photon counting |
| photon emittance |
photon exitance,
quantity |
photon exposure,
quantity |
photon flow,
quantity |
photon fluence,
quantity |
photon fluence rate,
quantity |
| photon flux |
photon irradiance,
quantity |
| photon quantities |
photon radiance,
quantity |
| photooxidation |
| photooxygenation |
| photopeak |
| photophoresis |
| photophosphorylation |
| photophysical processes |
| photopolymerization |
| photoreaction |
| photoreduction |
| photoresist |
| photosensitization |
| photosensitizer |
| photostationary state |
| photosynthesis |
| photosystem |
| photothermal effect |
| photothermography |
| phototransistor |
| photovoltaic cell |
| pH-rate profile |
| pH standard |
| phthaleins |
| phthalides |
| physical adsorption |
| physical network |
| physical quantity (measurable quantity) |
| physisorption (physical adsorption) |
| phytotoxicant |
| picoSI unit prefix |
| picrates |
| piezoluminescence |
| pile-up in radioanalytical chemistry |
| pinacols |
| PIN (p-intrinsic-n) diode |
| PIN semiconductor detector |
| pinocytosis |
| pitch |
| pitch-based carbon fibres |
| pitting corrosion |
| Pitzer strain |
| planar chirality |
| planar chromatography |
| planar film |
| planar stereoisomerism |
| Planck constant |
| plane angle |
| plasma in biology |
| plasma in spectrochemistry |
| plasma desorption ionization in mass spectrometry |
| plasmid |
| plastic flow |
| plastic transition |
| plateau border in surface chemistry |
plate height,
in chromatography |
plate number,
in chromatographyquantity |
| pleiotropic gene |
| ploidy |
| plug-flow in catalysis |
| plumbylenes |
| plumbylidenes |
| plume in atmospheric chemistry |
| plus, minus |
| pneumatic detector |
| point group |
| point of zero charge (p.z.c.) |
|
poise
unit |
| poison in catalysis |
| Poisson distribution |
| polar aprotic solvent |
| polar effect |
| polarity |
| polarizabilityquantity |
| polarization |
polarization,
in electrochemistryquantity |
| polarization error in spectrochemical analysis |
| polarized interphases |
| polarography |
| polar solvent |
| pollution (pollutant) |
| pollution rose |
| polyaddition |
| polychromator |
| polycondensation |
| polycrystalline graphite |
| polycyclic system |
| polydent |
| polydisperse medium |
| polydisperse polymer |
| polyelectrolyte |
| polyfunctional catalysis |
| polygranular carbon |
| polygranular graphite |
| polyhedral symbol |
| polyhedranes |
| polyions |
| polyketides |
| polymer |
| polymer blend |
| polymer crystal |
| polymer crystallite |
| polymerase chain reaction (PCR) |
| polymeric |
| polymeric stationary phase (material) in liquid chromatography |
| polymerization |
| polymer molecule |
| polymer network |
| polymer–polymer complex |
| polymer-poor phase |
| polymer-rich phase |
| polymer–solvent interaction |
| polymolecularity correction |
| polymorphic transition |
| polypeptides |
| polyprenols |
| polyquinanes (polyquinenes) |
| polysaccharides |
| polysulfanes |
| polysulfides |
| polytopal rearrangement |
| polytypic transition |
| pooled relative standard deviation |
| pooled standard deviation |
| population inversion |
| pore size distribution |
| Porod–Kratky chain in polymers |
| porosity |
| porous-layer open-tabular (PLOT) column
in chromatography |
| porphyrinogens |
| porphyrins |
| position-sensitive photomultiplier tube |
| positive feedback |
| positive ion in mass spectrometry |
| positron |
| positronium |
| post-column derivatization in chromatography |
| post-filter effect in luminescence spectroscopy |
| postprecipitation |
| potential at the point of zero charge (p.z.c.) |
| potential-determining (p.d.) ions |
potential energy,
 ,
quantity |
| potential-energy profile |
| potential-energy (reaction) surface |
| potential of a cell reaction |
| potential temperature |
| potentiation |
| potentiometer |
| potentiometric detection method
in electrochemical analysis |
| potentiometric selectivity coefficient |
power,
quantity |
| power level |
| pre-association |
| precipitation |
| precipitation fractionation of polymers |
| precipitation from homogeneous solution
(pfhs)
in analysis |
| precipitation titration |
| precision |
| precision of a balance |
| precision of a weighing |
| precision of indication of a balance |
| preconcentration in trace analysis |
| preconcentration coefficient
of a desired microcomponent in trace analysis |
| precursor in radioanalytical chemistry |
| precursor complex |
| precursor ion in mass spectrometry |
| predissociation |
| pre-equilibrium in solvent extraction |
| pre-equilibrium (prior equilibrium) |
pre-exponential factor,
quantity |
| preferential sorption in polymers |
| pre-filter effect in luminescence spectroscopy |
| premium coke |
| premix burner in flame spectroscopy |
| prenols |
| pre-polymer |
| pre-polymer molecule |
pressure,  quantity |
| pressure flow |
| pressure gradient correction factor
in gas chromatography |
| pressure-induced transition |
| pressure jump |
| pressure-sensitive detector |
| pretreatment of a catalyst |
| primary crystallization |
| primary current distribution |
| primary electrons (pe)
in in situ microanalysis |
| primary excitation of X-rays |
| primary isotope effect |
| primary kinetic electrolyte effect |
| primary kinetic isotope effect |
| primary mixture |
| primary particle in catalysis |
| primary photochemical process (primary
photoreaction)
|
| primary pH standards |
| primary pollutant in atmospheric chemistry |
| primary (photo)process |
| primary (photo)product |
| primary sample |
| primary standard |
| primary structure |
| primary structure
of a segment of a polypeptide |
| primitive change |
| principal group |
| principal ion in mass spectrometry |
| principal moments of inertia |
| principle of least nuclear motion |
| principle of microscopic reversibility |
| principle of minimum structural change |
prior distribution,
|
| prior equilibrium |
| priority |
probability,
|
probability density,  |
| probe in biotechnology |
| process |
| prochirality |
| prochirality centre |
| product |
| product-determining step |
| product development control |
| product ion |
productivity,
in biotechnologyquantity |
| product state distribution |
| pro-E, pro-Z |
| progenitor ion in mass spectrometry |
| program |
| programmed-flow chromatography (flow programming) |
| programmed-pressure chromatography (pressure
programming)
|
| programmed-temperature chromatography (temperature
programming)
|
| projection formula |
| prolate trochoidal mass spectrometer |
| promoter (gene technology) |
| promoter in catalysis |
| promotion |
| prompt coincidence |
| prompt neutrons |
| propagating reaction |
| propagation |
| propellanes |
| property |
| prophage |
| proportional counter |
| proportional counter tube |
| proportional gas-scintillation counter |
| proprochirality |
| pro-R, pro-S |
| pros in histidine nomenclature |
| prostaglandins |
| prostanoids |
| prosthetic group |
| proteases |
| protected lyophobic colloid |
| protective action in colloid chemistry |
| protein engineering |
| proteins |
| proteoglycan |
| proteome |
| protic |
| protide |
| protio |
| protium |
| protogenic (solvent) |
| protolysis |
| proton |
| proton affinity |
| protonated molecule in mass spectrometry |
| protonation constant |
| proton charge |
| proton magnetic momentconstant |
| proton magnetogyric ratio |
| proton number |
| proton rest massconstant |
| proton transfer reaction |
| protophilic (solvent) |
| protoplast |
| prototrophs |
| prototropic rearrangement (or prototropy) |
| pseudo acids |
| pseudo-asymmetric carbon atom |
| pseudo-axial |
| pseudo bases |
| pseudo-catalysis |
| pseudo-co-oligomer |
| pseudo-copolymer |
| pseudo-equatorial |
| pseudo-first-order rate coefficient |
| pseudo-first-order reaction |
| pseudohalogens |
| pseudomolecular rearrangement |
| pseudopericyclic |
| pseudo rate constant |
| pseudorotation |
| pseudo-unimolecular |
| pseudoureas |
| pseudo-zero-order reaction |
| psychosine |
| psychrometric hygrometer |
| psychrometry |
| puffing |
| puffing inhibitor |
| pulsatance |
| pulse amplitude analyser |
| pulse amplitude selector |
| pulse duration in electroanalytical chemistry |
| pulse height analyser |
| pulse reactor in catalysis |
| pump-probe technique |
| purine bases |
| pyramidal inversion |
| pyranoses |
| pyrimidine bases |
| pyro |
| pyroelectric detector |
| pyrolysis |
| pyrolysis-gas chromatography |
| pyrolytic carbon |
| pyrolytic graphite |
| pyrromethenes |
