Arsenic, surface chemistry

Over the past several years, the area of gas-phase transition metal ion chemistry has been gaining increasing attention from the scientific community [1-16]. Its appeal is manifold first, it has broad implications to a spectrum of other areas such as atmospheric chemistry, corrosion chemistry, solution organometallic chemistry, and surface chemistry secondly, an arsenal of gas phase techniques are available to study the thermochemistry, kinetics, and mechanisms of these "unusual" species in the absence of such complications as solvent and ligand... 

The surface chemistry of Li in ethereal solutions has been studied rigorously by several groups. Koch et al. [72-74] studied the surface layers formed on Li in THF and 2Me-THF solutions of LiAsF6, which appear as brown films covering the electrodes. They concluded that these films are polymers of lithiated arsenic oxide that contain additional functional groups such as F, RCT, etc. However, these conclusions did not result from direct spectroscopic studies of Li surfaces. Important, indirect information on the composition of the surface films formed... 

Fuller, C. C., J. A. Davis, and G. A. Waychunas. 1993. Surface chemistry of ferrihydrite Part 2. Kinetics of arsenate adsorption and coprecipitation. Geochim. Cosmochim. Acta 57 2271-2282. 

Waychunas, G.A. et al., Surface chemistry of ferrihydrite Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate, Geochim. Cosmochim. Acta, 57, 2251, 1993. 

He has contributed to research on the interface between soil chemistry and mineralogy and soil biology. His special areas of research include the formation mechanisms of aluminum hydroxides and oxyhydroxides, the surface chemistry and reactivities of short-range-ordered precipitation products of Al and Fe, the influence of biomolecules on the sorption and desorption of nutrients and xenobiotics on and from variable charge minerals and soils, the factors that influence the sorption and residual activity of enzymes on phyllosilicates, variable charge minerals, organomineral complexes, and soils and the chemistry of arsenic in soil environments. 

Warburton WK (1986) Filtered energy dispersive detector (EDD) arrays superior detectors of EXAFS from very diluted solutions. Nucl Inst Methods A246 541-546 Waychunas GA, Brown GE (1994) Fluoresence yield XANES and EXAFS experiments Applications to highly dilute and surface samples. Adv X-ray Anal 37 607-617 Waychunas GA, Rea BA, Fuller CC, Davis JA (1993) Surface chemistry of ferrihydrite. Part I. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate. Geochim Cosmocliim Acta 57 2251-2269... 

Besides immediate practical applications in fields such as drug design, molecular surfaces contribute to the transformation of modernizing the conceptual arsenal of chemistry, long dominated by line drawings of chemical bonds of structural formulas. Molecular surfaces have led to a true appreciation of the three-dimensional aspects of molecules, important in all branches of chemistry. Precise methods for the analysis of the shapes of these surfaces are available using the topological shape codes and provide tools for the numerical evaluation of such elusive but important properties as measures of molecular similarity and shape complementarity. 

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