GEOC 66 |
| Thomas P. Trainor, Department of Chemistry and Biochemistry, University of Alaska Fairbanks, PO Box 756160, Fairbanks, AK 99775-6160, Peter J. Eng, Consortium for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, Jeffrey G. Catalano, Department of Geological and Environmental Sciences, Stanford University, Bldg. 320, Room 118, Stanford, CA 94305-2115, Gordon E. Brown Jr., Department of Geological and Environmental Sciences, Stanford Synchrotron Radiation Laboratory, SLAC, 2575 Sand Hill Road, Menlo Park, CA 94025, and Glenn Waychunas, Earth Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720. |
| We have used Crystal Truncation Rod (CTR) diffraction to determine the structure of the hydrated hematite (1-102) surface. The best fit model to our CTR data is consistent with removing the top-most iron atom from the otherwise stoichiometric termination. While this leads to a non-stoichiometric surface model, excess charge is likely compensated for by binding of protons at the exposed surface oxygens. This result suggests that the hematite (1-102) surface has surface hydroxyl groups which are singly-, doubly- and triply-coordinated with Fe, similar to our previous findings on the alumina (1-102) surface. The similarity of these models is in contrast to our previous comparison of the alumina and hematite (0001) surfaces which were found to have substantially different surface terminations. Implications for surface reactivity based on the coordination environments of the surface functional groups will be discussed. |
|
Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
8:00 AM-11:40 AM, Tuesday, March 30, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |