IMOGOLITE SYNTHESIS AT 25 degree C.

Imogolite was synthesized at 25 degree C by aging partially neutralized solutions containing monomeric silicic acid and polymeric hydroxy-aluminum ions for 7 years. Solutions having an initial Si/Al molar ratio of about 0. 5 and pHs of 4. 0-4. 5 produced the largest yields of imogolite, followed by those having an initial Si/Al ratio of about 1, although imogolite was not the principal product. Electron microscopic examination showed a small amount of imogolite fibers embedded in a noncrystalline gel-like substance. Traces of imogolite were detected in solutions having an initial Si/Al ratio of about 2, but no imogolite was found by electron microscopy in products from solutions having an initial Si/Al ratio of about 4.