Supplementary XRD Material for "Experimental Constraints on Barium Isotope Fractionation during Adsorption-Desorption Reactions: Implications for Weathering and Erosion Tracer Applications"

<p><strong>Repository Overview:</strong> Supplementary powder X-ray diffraction (XRD) data for the study "Experimental Constraints on Barium Isotope Fractionation during Adsorption-Desorption Reactions: Implications for Weathering and Erosion Tracer Applications"</p> <p><strong>Data Provided:</strong> Powder X-ray diffractograms of the minerals used in the laboratory batch experiments. Pow</p> <p><strong>Minerals Analysed:</strong></p> <p><span>Clay Minerals:</span></p> <ul> <li>Kaolinite (KGa-2): purchased from the Clay Minerals Society (CMS).</li> <li>Montmorillonite (SWy-2): purchased from the Clay Minerals Society (CMS).</li> </ul> <p><span>Iron Oxyhydroxide Minerals:</span></p> <ul> <li>Goethite synthesised under alkaline conditions in the laboratories at the Department of Earth Sciences, University of Cambridge, following the method detailed in Schwertmann and Cornell (2008).</li> <li>2-line ferriydrite synthesised in the laboratories at the Department of Earth Sciences, University of Cambridge, following the method detailed in Schwertmann and Cornell (2008) methods.</li> </ul> <p><strong>XRD Methods:</strong></p> <ul> <li>Instrument and Set Up: Theta-Theta D8 Bruker Advance diffractometer with a Mo anode, Lynxeye XE-T PSD detector and 2 mm divergent slit.</li> <li>Sample Preparation: Zero-background monocrystalline silicon plate was used to minimize sample mass. The X-ray diffractogram of the silicon plate was measured prior to each sample measurement.</li> <li>Clay Minerals: 0.02&deg; step size and a 3s step rate.</li> <li>Iron Oxyhydroxide Minerals: 0.03&deg; increments and a 1s step rate.</li> </ul> <p><strong>Purpose of XRD Analyses:</strong></p> <ul> <li>To verify the correct synthesis of iron oxyhydroxide phases and to detect impurities.</li> <li>To monitor any mineralogical changes that occurred during adsorption-desorption reactions with water.</li> </ul> <p><strong>Data Format</strong></p> <table> <tbody> <tr> <td><strong>Column Name</strong></td> <td><strong>Description</strong></td> <td><strong>Unit</strong></td> </tr> <tr> <td>twotheta</td> <td>2&theta;</td> <td>&deg;</td> </tr> <tr> <td>intensity</td> <td>intensity</td> <td>counts per second (cps)</td> </tr> <tr> <td>ID</td> <td>mineral ID</td> <td>unitless</td> </tr> <tr> <td>mineral</td> <td>mineral name</td> <td>unitless</td> </tr> <tr> <td>duration</td> <td>reaction duration</td> <td>minutes</td> </tr> </tbody> </table> <p><strong>Extra Notes</strong></p> <p>A reaction duration of zero minutes corresponds to an unreacted mineral sample.</p>