Preparation: |
prepared through slow air-oxidation of a 50 mM Fe<2+> and 100 mM bicarbonate solution over two days, and then centrifuged and washed three times with 18 MΩ water. The resultant slurry was then oven dried at 70 °C for two hours, resulting in a mineral powder that was then gently ground with a mortar and pestle to homogenize the sample. |