Copper silicide

Copper silicide
Identifiers
CAS Number	12159-07-8^Y
3D model (JSmol)	Interactive image
ChemSpider	29356049
ECHA InfoCard	100.032.066
EC Number	235-286-8
PubChem CID	6336988
CompTox Dashboard (EPA)	DTXSID101014289
InChI InChI=1S/5Cu.Si Key: JUZTWRXHHZRLED-UHFFFAOYSA-N
SMILES [Si].[Cu].[Cu].[Cu].[Cu].[Cu]
Properties
Chemical formula	Cu₅Si
Molar mass	345.8155 g/mol
Appearance	silver powder
Melting point	825 °C (1,517 °F; 1,098 K)
Hazards
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 mg/m³ (as Cu)^[1]
REL (Recommended)	TWA 1 mg/m³ (as Cu)^[1]
IDLH (Immediate danger)	TWA 100 mg/m³ (as Cu)^[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Chemical compound

Copper silicide can refer to either Cu₄Si^[2] or pentacopper silicide, Cu₅Si.

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 solid crystalline material is a silvery solid that is insoluble in water. It forms upon heating mixtures of copper and silicon.

Applications

Copper silicide thin film is used for passivation of copper interconnects, where it serves to suppress diffusion and electromigration and serves as a diffusion barrier.^[3]^{[better source needed]}

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:^[4]

2 CH₃Cl + Si → (CH₃)₂SiCl₂

References

^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
^ CRC Handbook of Chemistry and Physics, 49th edition, "Physical constants of inorganic compounds" (p. B-198).
^ "Copper silicide passivation for improved reliability - US Patent 6869873". Archived from the original on 2007-09-29. Retrieved 2007-02-10.
^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.