Cobalt compounds silicides

Apart from antimony, there are other good promoters of the direct synthesis of methylchlorosilanes, which increase the yield of dimethyldichlorosilane, such as arsenic and zinc chloride. If it is necessary to increase the yield of alkylhydridechlorosilanes, one should use univalent copper chloride, cobalt, and titanium. The addition of tin or lead into contact mass increases the yield of dimethyldichlorosilane up to 70% the yield of ethyldi-chlorosilane is increased to 50-80% when contact mass receives 0.5-2% of calcium silicide (Ca2Si). In the synthesis of phenylchlorosilanes effective promoters are zinc, cadmium, mercury or their compounds. In particular, the introduction of zinc oxide (up to 4%) into contact mass may increase the diphenyldichlorosilane content up to 50%, and the introduction of a mixture of zinc oxide and cadmium chloride, even up to 80%. 

Hence, none of the two above-mentioned criteria can be used as a reliable basis for predicting the sequence of occurrence of chemical compound layers in multiphase binary systems. The experimental data on the formation of nickel and cobalt silicides provides additional evidence for the validity of this conclusion. 

The binary cobalt and yttrium silicides aie in good agreement with more recent data and are discussed in combination with the systems Ce-Co-Si and Y-Ni-Si, respectively. Mutual solid solubilities of binary compounds have been found to be... 

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