Born Feb. 19, 1859, on the estate of Wijk, near Uppsala; died Oct. 2, 1927, in Stockholm. Swedish physical chemist. Member of the Swedish Academy of Sciences (1901). Honorary member of the academies and societies of many countries, including the Academy of Sciences of the USSR (1926). Honorary doctor of such universities as Cambridge, Oxford, and Birmingham. Originator of the theory of electrolytic dissociation, which is one of the greatest chemical generalizations of the 19th century.

Arrhenius graduated from the University of Uppsala. Beginning in 1882 he worked in the Physical Institute of the Academy of Sciences in Stockholm; in 1895 he became professor at the University of Stockholm; in 1905 he became director of the Nobel Institute. Beginning the study of the conductivity of dilute aqueous solutions of acids and other electrolytes in 1882, Arrhenius came to the conclusion in 1887 that in solution the molecules of electrolytes dissociate into electrically charged components—that is, ions. The theory of electrolytic dissociation elucidated the connection between phenomena that would seem to be independent of each other—for example, between conductivity and the reactive capacity of electrolytes. His theory served as the basis for further work in the area of solutions by W. Ost-wald, J. van’t Hoff, and others. Since solutions are widespread throughout nature and are important in practical work, Arrhenius’ discovery helped clarify complex problems not only in the areas of physics and chemistry but also in biology, geology, and other sciences. However, Arrhenius’ theory did not entirely take into account the complexity of the interactions of the dissolved particles with each other and with the solvent; his quantitative conclusions were found to apply only to highly dilute aqueous solutions. Further study of concentrated solutions of strong electrolytes and nonaqueous solutions led to the formulation of the current theory about solutions, which does not exclude Arrhenius’ theory but extends and complements it with new generalizations. Arrhenius is also responsible for important discoveries in the area of the study of the rates of chemical reactions; he derived the equation linking the rate of a reaction with temperature (Arrhenius’ equation, 1889).

Arrhenius engaged in research in astronomy and astrophysics (for example, the temperatures of planets, the theory of the sun’s corona, and the formation and evolution of heavenly bodies) and in the application of physical and chemical laws to biological processes. Arrhenius’ hypothesis about the immortality of living matter and about the transfer of embryonic life from one planet to another was mistaken. He was awarded the Nobel Prize in 1903.