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- D. C. Golden
- Department of Soil and Crop Sciences, Texas A&M University, College Station, 77843.
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- C. C. Chen
- Department of Soil and Crop Sciences, Texas A&M University, College Station, 77843.
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- J. B. Dixon
- Department of Soil and Crop Sciences, Texas A&M University, College Station, 77843.
説明
<jats:p> Todorokite of chemical composition (Mg <jats:sub>0.77</jats:sub> Na <jats:sub>0.03</jats:sub> )(Mg <jats:sub>0.18</jats:sub> Mn <jats:sup>2+</jats:sup> <jats:sub>0.60</jats:sub> Mn <jats:sup>4+</jats:sup> <jats:sub>5.22</jats:sub> ) O <jats:sub>12</jats:sub> ⋅ 3.07 H <jats:sub>2</jats:sub> 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. </jats:p>
収録刊行物
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- Science
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Science 231 (4739), 717-719, 1986-02-14
American Association for the Advancement of Science (AAAS)