THE ESSENTIALITY OF SILICON IN BIOLOGY

Of the fifteen or so elements considered to be essential to life silic on is perhaps the most mysterious in that no stable attachment to the organic molecules of life has been demonstrated. This article draws at tention to the inorganic chemistry of silicic acid and its interaction s with basic metal ions in aqueous solution at circumneutral pH. The i nteractions with aluminium are of particular interest because aluminiu m is toxic when it enters physiology. It is normally excluded and the role of silicic acid in this exclusion is discussed.