Proton Affinity
| Formula / Notation | PA = −ΔH(B + H⁺ → BH⁺) |
|---|---|
| Also Known As | Gas-phase basicity, intrinsic basicity, proton affinity energy |
What is Proton Affinity?
Proton affinity (PA) is a measure of the intrinsic basicity of a molecule — specifically, the negative of the enthalpy change when a proton (H⁺) is added to a neutral molecule in the gas phase: B + H⁺ → BH⁺. Unlike pKb (which includes solvation effects), proton affinity reflects only the intrinsic tendency to bind a proton. Higher proton affinity means stronger gas-phase basicity.
Formula & Notation
Other Names / Synonyms: Gas-phase basicity, intrinsic basicity, proton affinity energy
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
Proton affinity (PA) is a measure of the intrinsic basicity of a molecule — specifically, the negative of the enthalpy change when a proton (H⁺) is added to a neutral molecule in the gas phase: B + H⁺ → BH⁺. Unlike pKb (which includes solvation effects), proton affinity reflects only the intrinsic tendency to bind a proton. Higher proton affinity means stronger gas-phase basicity.
Understanding gas-phase acid-base chemistry. Atmospheric chemistry calculations. Mass spectrometry (understanding ionization and fragmentation). Catalysis on solid surfaces. Chemical ionization mass spectrometry (reagent gas selection). Computational chemistry benchmarking.
Theoretical concept — no direct safety concerns.
The formula or notation for Proton Affinity is: PA = −ΔH(B + H⁺ → BH⁺)