An equation that describes the molar conductivities of strong electrolytes at low concentration, i.e. Λm=Λ0m – Κc½, where Λm is the molar conductivity, Λ0m is the limiting molar conductivity (the molar conductivity in the limit of zero concentration when the ions do not interact with each other), Κ is a coefficient related to the stoichiometry of the electrolyte, and c is the concentration of the electrolyte. It is possible to express Λ0m as a sum of the contribution of each of its ions. The Kohlrausch equation was first stated in the 19th century by the German chemist Friedrich Kohlrausch (1840–1910) as the result of a considerable amount of experimental work. With its characteristic c½ dependence, the equation is explained quantitatively by the existence of an ionic atmosphere round the ion as analysed by the Debye-Hückel-Onsager theory.