9418206 Fink This award provides funding for fundamental studies of minerals employing electron energy-loss spectroscopic techniques. The general goal of the spectrometric studies is to gain an understanding of the bonding and oxidation state of iron in minerals and of the bonding and structure of crystalline and opaline silica polymorphs . One important specific objective of the studies is to determine the feasibility of using electron energy-loss spectroscopy to measure the ratio of Fe2+ to Fe3+ in silicates with a spatial resolution of nanometers in a scanning transmission electron microscope fitted with a special electron detector. Determination of iron oxidation states at the nanometer scale is not now possible but would be an important step in understanding the chemistry of minerals and in reconstructing the geological conditions of their formation. ***
