The proton affinity (PA, Epa) of an anion or of a neutral atom or molecule is the negative of the enthalpy change in the reaction between the chemical species concerned and a proton in the gas phase:[1]
These reactions are always exothermic in the gas phase, i.e. energy is released (enthalpy is negative) when the reaction advances in the direction shown above, while the proton affinity is positive. This is the same sign convention used for electron affinity. The property related to the proton affinity is the gas-phase basicity, which is the negative of the Gibbs energy for above reactions,[2] i.e. the gas-phase basicity includes entropic terms in contrast to the proton affinity.
^"Proton affinity." Compendium of Chemical Terminology.
^"Gas-phase basicity." Compendium of Chemical Terminology.
The protonaffinity (PA, Epa) of an anion or of a neutral atom or molecule is the negative of the enthalpy change in the reaction between the chemical...
A superbase is a compound that has a particularly high affinity for protons. Superbases are of theoretical interest and potentially valuable in organic...
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with...
A proton is a stable subatomic particle, symbol p , H+, or 1H+ with a positive electric charge of +1 e (elementary charge). Its mass is slightly less than...
to the macromolecule. A simplified mechanism can be formulated if the affinity of all binding sites can be considered independent of the number of ligands...
higher protonaffinity. The methanide ion CH−3 was the strongest known base before lithium monoxide anion was discovered. LiO− has a protonaffinity of ~1782...
definition, a superacid is a medium in which the chemical potential of the proton is higher than in pure sulfuric acid. Commercially available superacids...
superbases ever, with the ortho isomer being the strongest, with a protonaffinity of 1,843.987 kJ/mol (440.723 kcal/mol). The meta isomer is the second-strongest...
ions. These ions experience protonation, H+ + SO2− 4↔ HSO− 4, such that the total scale includes the effect of both protons (free hydrogen ions) and hydrogen...
species are amphiprotic molecules, which can either donate or accept a proton (H+). This is what "amphoteric" means in Brønsted–Lowry acid–base theory...
The proton (H+) is one of the strongest but is also one of the most complicated Lewis acids. It is convention to ignore the fact that a proton is heavily...
number Equilibrium chemistry Extraction Hammett acidity function pH Protonaffinity Self-ionization of water Titration Lewis acid catalysis Frustrated...
than one proton. The constant for dissociation of the first proton may be denoted as Ka1, and the constants for dissociation of successive protons as Ka2...
the chemical formula HA {\displaystyle {\ce {HA}}} , to dissociate into a proton, H + {\displaystyle {\ce {H+}}} , and an anion, A − {\displaystyle {\ce...
the compound OgH+ exhibits a dissociation energy (in other words protonaffinity of oganesson) that is smaller than that of RnH+. The bonding between...
number Equilibrium chemistry Extraction Hammett acidity function pH Protonaffinity Self-ionization of water Titration Lewis acid catalysis Frustrated...
Radom, Leo (2016). "Preparation of an ion with the highest calculated protonaffinity: ortho-diethynylbenzene dianion". Chemical Science. 7 (9): 6245–6250...
compound which acts as a base. Organic bases are usually, but not always, proton acceptors. They usually contain nitrogen atoms, which can easily be protonated...
number Equilibrium chemistry Extraction Hammett acidity function pH Protonaffinity Self-ionization of water Titration Lewis acid catalysis Frustrated...
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