On the Aging of Ferrous Hydroxide and Ferrous Carbonate

Interest in the aging of metal hydroxide has increased greatly during the past few years and it is due, no doubt, mainly to the fact that certain metal hydroxides have become useful for the isolation of enzymes and vitamins. The selective adsorption properties of these hydroxides, aluminum hydroxide for example, make them suitable for these purposes. Their surface forces make it possible to separate unstable organic groups or compounds which otherwise would not be obtained at all, or only with extreme difficulty. But the theoretical interest in the aging phenomenon has also become more intense, since it is possible by modern methods, especially by that of X-ray spectroscopy, to follow the changes taking place in the hydroxides with time, and thus to come to certain conclusions as to the nature of the adsorption process. In this connection we have in mind particularly the recent work of Fricke and Wever (1) on aluminum hydroxide. Our own work is concerned entirely with ferrous hydroxide and ferrous carbonate. These substances are widely distributed in nature, and almost certainly play a very large part in many biological processes. Our experiments were not originally planned with the purpose of getting data on the aging problem. But they led us to believe and finally convinced us that ferrous hydroxide and ferrous carbonate, at the instant of precipitation, possess properties which disappear very rapidly with time. Since it was known that ferrous hydroxide and ferrous carbonate are exceedingly autoxidizable and, as a result of the absorption of oxygen, form a series of compounds it was necessary to adopt two distinct types of experiments in our study. The experiments had to be performed in: (1) the entire absence of oxygen ;