Synthesis of Todorokite
- 14 February 1986
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 231 (4739) , 717-719
- https://doi.org/10.1126/science.231.4739.717
Abstract
Todorokite of chemical composition (Mg 0.77 Na 0.03 )(Mg 0.18 Mn 2+ 0.60 Mn 4+ 5.22 ) O 12 ⋅ 3.07 H 2 O was synthesized by a two-step procedure. First, sodium birnessite was synthesized and magnesium was exchanged for sodium to form magnesium birnessite, which was autoclaved under a saturated steam pressure at 155°C for 8 hours to form well-crystallized todorokite. Synthesized todorokite particles consisted of fibers extending from a central plate. The plate itself was made of twinned fibers forming a trilling pattern. The infrared spectra and x-ray diffraction patterns were similar to those of natural todorokite samples. Calcium birnessite and nickel birnessite, when autoclaved under conditions similar to those for magnesium birnessite, yielded a todorokite structure. However, the formation of todorokite from calcium and nickel birnessite was less extensive.Keywords
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