Figure 3.

Cu Kα XRD patterns of smectites and their oxidative products. In (a) and (b), the region from 2θ from 8° to 18° is omitted from the patterns because of a peak produced by the dome of the sample holder. Peaks associated with nanoparticulate hematite are labeled ‘h’. Small sharp peaks originate from minor quartz introduced by grinding sample with an agate mortar and pestle. c) The XRD 060 region for samples A, B, C, and D and their oxidative products, with colors as in a). Dotted lines correspond to the 060 peak position for each unaltered sample. d₀₆₀ (in Å) for unaltered samples are also provided.