A term to denote the tendency of a particular solvent to promote ionization of an uncharged or, less often, charged solute. The term has been used both in a kinetic and in a thermodynamic context. See also Dimroth-Reichardt ET parameter, Grunwald-Winstein equation, Z-value

A compound containing a large organic cation or anion which possesses a long unbranched hydrocarbon chain, e.g. H3C(CH2)nCO2-M+ H3C(CH2)nSO3-M+ H3C(CH2)nN(CH3)3+X- (n > 7). The existence of distinct polar (hydrophilic) and non polar (hydrophobic) regions in the molecule promotes the formation of micelles in dilute aqueous solution. amphiprotic ( [..]

The uncatalysed cleavage of one or more covalent bonds resulting from exposure of a compound to a raised temperature, or a process in which such cleavage is an essential part. See also pyrolysis

See Gibbs energy diagram, potential-energy profile

An activated complex, often characterized by the superscript , is defined as that assembly of atoms which corresponds to an arbitrary infinitesimally small region at or near the col (saddle point) of a potential energy surface. See also transition state

The assembling of separate molecular entities into any aggregate, especially of oppositely charged free ions into ion pairs or larger and not necessarily well-defined clusters of ions held together by electrostatic attraction. The term signifies the reverse of dissociation, but is not commonly used for the formation of definite adducts by colligati [..]

(IUPAC Recommendations 1994) B Continue from terms starting with A

A chemical species or molecular entity having an available pair of electrons capable of forming a covalent bond with a hydron (proton) (see Brønsted base) or with the vacant orbital of some other species (see Lewis base). See also hard base, superbase

For Brønsted bases it means the tendency of a compound to act as hydron (proton) acceptor. The basicity of a chemical species is normally expressed by the acidity of the conjugate acid (see conjugate acid-base pair). For Lewis bases it relates to the association constants of Lewis adducts and -adducts

See acidity function