Copper silicide (Cu5Si), also called pentacopper silicide, is a binary compound of silicon with copper. It is an intermetallic compound, meaning that it has properties intermediate between an ionic compound and an alloy. This a solid crystalline material is a silvery solid that is insoluble in water. It forms upon heating mixtures of copper and silicon.
Copper silicide thin film is used for passivation of copper-based chips, where it serves to suppress diffusion and electromigration and serves as a diffusion barrier.
Copper silicides are invoked in the Direct process, the industrial route to organosilicon compounds. In this process, copper, in the form of its silicide, catalyses the addition of methyl chloride to silicon. An illustrative reaction affords the industrially useful dimethyldichlorosilane:
- 2 CH3Cl + Si → (CH3)2SiCl2
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- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419.