On the equilibration of solid phases. Some thoughts on Ostwalds contributions

Formation of Solids / Rule of Successive Reaction Steps Ostwald-Ripening This paper discusses two of Ostwalds experimental observations which the literature connects with his name. The generalized conclusions Ostwald inferred are presented and discussed. His discoveries deal essentially with the formation of solid phases. Later both played important roles in the field of solid state reactions. The two items are: 1. Ostwalds rule of successive reaction steps (ORS-rule) and 2. the Ostwald-ripening process (ORP-process). Since material scientists and engineers try to obtain special properties of a solid by establishing its microstructure, Ostwalds discoveries and ideas do influence the field of materials science till nowadays. In what follows his farsightedness and his limitations are placed in the context of solid state physical chemistry and its history.