Silicon tetrachloride, reaction + alkali

Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between silicon carbide and a variety of compounds at relatively high temperatures. Sodium silicate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal silicide. Silicon carbide decomposes in fused alkalies such as potassium chromate or sodium chromate and in fused borax or cryolite, and reacts with carbon dioxide, hydrogen, air, and steam. Silicon carbide, resistant to chlorine below 700°C, reacts to form carbon and silicon tetrachloride at high temperature. SiC dissociates in molten iron and the silicon reacts with oxides present in the melt, a reaction of use in the metallurgy of iron and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new silicon nitride-bonded type exhibits improved resistance to cryolite. 

These higher chlorides of silicon hydrolyze in the same way as does the tetrachloride, and they likewise undergo similar reactions with Grignard reagents and with sodium alkyls or aryls.30 Under some conditions, however, the silicon-silicon bond is cleaved by sodium.31 The silicon-silicon chains are destroyed by the action of aqueous alkalies, liberating hydrogen at the rate of one molecule of H2 per silicon-silicon bond, just as are the higher silanes. 

Carbon tetrachloride is a noncombustible liquid. Explosion may occur when this compound is mixed with alkali metals such as sodium, potassium, lithium, or their alloys or finely divided aluminum, magnesium, calcium, barium, beryllium, and other metals on heating or impact. Reactions with hydrides of boron or silicon, such as diborane, disilane, trisilane, or tetrasilane, can be explosively violent. When mixed with dimethyl formamide and heated, carbon tetrachloride may explode (Kittila 1967). Its mixture with potassium terf-butoxide may ignite. Its reaction with fluorine or a halogen fluoride is generally vigorous and may become violent on heating. A violent reaction occurs with hypochlorites. 

---