24 REVIEW AND BIBLIOGRAPHY 



LITERATURE. 



MOISSAN. Sur le solubilite du carbone dans le rhodium, I'iridium, et le palladium. 



C. R. 123, p. 16, or Bull. Soc. Chim. (1896) [3] 16, p. 1292; Abs. J. Chem. Soc. 



(1896) 70, pt. 2, p. 609. See also Abs. J. Chem. Soc. (1893) p. 320. 

 MoisSAN. Research on the metallic carbides. Chem. News (1896) 74, p. 15. 



SILICON AND CARBON. 



The compound of carbon and silicon known as carborundum (CSi) is 

 of great commercial value, being a good abrasive. Its hardness is between 

 that of corundum and the diamond. A compound is mentioned by Colson 

 which has the formula CgSi, and a doubtful compound C7Si2Al is also 

 mentioned in chemical literature. 



On a large scale carborundum is made from coke and sand, these being 

 mixed with salt and sawdust before submitting to the electric heat. The 

 charge is put in a long box-shaped furnace surrounding a coarse carbon 

 core which extends between the electrodes. These are from six to eight 

 feet apart, from one to nine carbons being in each end of the furnace. 

 The current passes from eight to ten hours. CSi forms long needle- 

 shaped crystals usually of a greenish-yellow color, sometimes blue. It is 

 unacted upon by mineral acids, decomposed by fusion with alkalies, and 

 oxidizable by PbCr04. The crystals are infusible except in the electric 

 arc. An amorphous product of about the same composition is formed at 

 some distance from the carbon core and beyond the zone in which the 

 crystalline product is found. 



The patents for making carborundum are owned by Mr. Acheson in 

 this country and in a number of European countries. It is found to be 

 very useful as an abrasive, and its introduction into the mechanical arts 

 has been rapid. 



The di-carbide of silicon, of Colson, is made by passing a stream of 

 C2H4 or H2 saturated with benzine vapors over silicon for several hours. 

 The silicon is contained in a porcelain tube and heated to a bright heat 

 during the conduction of the gas. SiC2 is decomposed by KOH or by a 

 mixture of PbCr04 and PbO, but is not acted upon even at red heat by 

 acids, oxygen, or chlorine. 



Tetra-silico-carbo-sulphide, Si4C4S, is formed by conducting CSg vapors 

 over white-hot silicon contained in a porcelain vessel. Other products 

 are produced at the same time, and hence the contents of the dish are 

 treated with hot KOH solution, and with HF. After this treatment the 

 above compound remains as a greenish powder, decomposable by boiling 

 HF, H2S being evolved. It oxidizes to SisCoO. 



Silicon nitro-carbide (CaSigN) results when Si is heated in the presence 

 of C and N, or in cyanogen, or in the presence of certain carbonaceous 

 substances in an atmosphere of nitrogen. 



