Metalloid anions

Resistance to heavy metals including Hg may be mediated by plasmid-borne genes. Further discussion of resistance to metal cations and metalloid anions is given in Chapter 3, Part 4. 

Homobimetallic species of the structure R2MMR2, M = As, Sb, Bi, are compounds formally containing M in the oxidation state II and the electrochemical reduction of these dimeric compounds is therefore described in this separate section together with a summary of the typical reactions of the metalloid anions formed in the reduction process. 

Independently of the choice of the polar aprotic solvent, the reduction of Pli2MMPh2 is a chemically irreversible two-electron reduction leading to formation of two metalloid anions (equation 71). 

The kinetics of the reaction (equation 83) of a series of electrogenerated metalloid anions including Ph2As , Ph2Sb and Ph2Bi with alkyl halides have been studied in DME . ... 

VIBRATIONAL SPECTROSCOPY Infrared and Raman spectroscopies have proven to be useful techniques for studying the interactions of ions with surfaces. Direct evidence for inner-sphere surface complex formation of metal and metalloid anions has come from vibrational spectroscopic characterization. Both Raman and Fourier transform infrared (FTIR) spectroscopies are capable of examining ion adsorption in wet systems. Chromate (Hsia et al., 1993) and arsenate (Hsia et al., 1994) were found to adsorb specifically on hydrous iron oxide using FTIR spectroscopy. Raman and FTIR spectroscopic studies of arsenic adsorption indicated inner-sphere surface complexes for arsenate and arsenite on amorphous iron oxide, inner-sphere and outer-sphere surface complexes for arsenite on amorphous iron oxide, and outer-sphere surface complexes for arsenite on amorphous aluminum oxide (Goldberg and Johnston, 2001). These surface configurations were used to constrain the surface complexes in application of the constant capacitance and triple layer models (Goldberg and Johnston, 2001). 

In the application of surface complexation models to clay minerals or to soils dominant in clays, the assumption is often made that metal ion adsorption occurs primarily on the aluminol and silanol groups of clay edges. The effect of the permanent charge sites on the adsorption process may not be considered. This simplification may be inappropriate, particularly for metal and metalloid anions, since repulsive electrostatic forces emanating from clay faces may spill over and affect the adsorption process on clay edges (Secor and Radke, 1985). 

Modification of V205 was investigated for propene oxidation to saturated aldehydes, acrolein, etc. The impurities added to V205 may be classified as falling into two groups acid (metalloid) anions of S04, P206, and other alkali cations such as Na, K, etc. 

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