Electrolytic conductance

(physical chemistry) The transport of electric charges, under electric potential differences, by charged particles (called ions) of atomic or larger size.

The transport of electric charges, under electric potential differences, by particles of atomic or larger size. This phenomenon is distinguished from metallic conductance, which is due to the movement of electrons. The charged particles that carry the electricity are called ions.

Positively charged ions are termed cations; the sodium ion, Na⁺, is an example. The negatively charged chloride ion, Cl⁻, is typical of anions. The negative charges are identical with those of electrons or integral multiples thereof. The unit positive charges have the same magnitude as those of electrons but are of opposite sign. Colloidal particles, which may have relatively large weights, may be ions, and may carry many positive or negative charges. Electrolytic conductors may be solids, liquids, or gases. Semiconductors have properties that are intermediate between the metallic and electrolytic types. See also Electrochemistry; Electromotive force (cells).

Conductances are usually reported as specific conductances κ, which are the reciprocals of the resistances of cubes of the materials, 1 cm (0.39 in.) in each dimension, placed between electrodes 1 cm square, on opposite sides. These units are sometimes called mhos, that is, ohm spelled backward. Conductances of solutions are usually measured by a method in which a Wheatstone bridge is employed.