Oxides donor-like impurities

Note that the impurities exert opposite influences on the reaction in the dark. The oxidation of CO, like any acceptor reaction, is retarded by acceptor impurities (increase of tB ) and accelerated by donor impurities (decrease of e3 ). As a matter of fact, according to Parravano s data (61)... 

Real oxide films usually are nonstoichio-metric because of an excess of metal ions or a deficiency of oxygen ions. Moreover, foreign ions like protons or impurities can contribute to the donors, acceptors or traps in the band gap. Defect concentrations N of passive films are very high, usually in the range from 10 to 10 cm (Table 1). The value of N obtained from capacity... 

TSeT)2-halides combine high room temperature conductivity (o = 2500 Qcm ) with high thermal stability up to over 250 °C (see Fig. l).They are, however, practically insoluble even in exotic organic solvents. Only the donor TSeT itself shows limited solubility in high boiling polar solvents. Until recently pure 2 1 halides could only be made by electrocrystallization in nitrobenzene in the presence of an organic ammonium halide as electrolyte. Chemical pathways like oxidation with Cl2-gas or ferrous chloride lead to impure products mainly due to overoxidation of the donor. 

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