Silicon Carbide - SiC

What is Silicon Carbide?

Silicon carbide, also commonly known as Carborundum, is a compound of silicon and carbon. Silicon carbide is a semiconductor material as an emerging material for applications in semiconductor devices. Silicon carbide was discovered by Pennsylvanian Edward Acheson in 1891. It is one of the most important industrial ceramic materials. Plays a key role in the industrial revolution and is still widely used as an abrasive and steel additive and structural ceramic.

IUPAC Name – Methanidylidynesilanylium

SiC Silicon Carbide Density 3.21 g/cm³ Molecular Weight/ Molar Mass 40.11 g/mol Melting Point 2,730 °C Compound Formula SiC

Silicon Carbide Structure – SiC

Bonding in Silicon Carbide – SiC

Silicon carbide crystallises in a close packed structure covalently bonded to each other. The atoms are arranged so that two primary coordination tetrahedral where four carbon and four silicon atoms are bonded to a central Si and C atoms are formed. These tetrahedra are linked together through their corners and stacked to form polar structures.

The tetrahedral units are linked together through their corners and stacked to form polar structures called Polytypes.

Physical Properties of Silicon Carbide – SiC

Odour No odour Appearance Black grey to green powder, grey solid Specific Density 3.21 g/cm3 Solubility Insoluble in water, alcohol, and acid.

Chemical Properties of Silicon Carbide – SiC

• It possesses interesting electrical properties due to its semiconductor characteristics, the resistance of different compositions varying by as seven orders of magnitude.
• Resistant to most organic and inorganic acids, alkalis and salts in a variety of concentrations except to hydrofluoric acid and acid fluorides.

Uses of Silicon Carbide – SiC

• Used in the manufacture of fast, high temperature and high voltage devices.
• Used in lining work for its uniformity abrasion resistance and dimensional stability.
• Used in the manufacture of electronic appliances such as light emitting diodes (LEDs) and detectors.

Frequently Asked Questions

What are the key uses of silicon carbide?

Silicon carbide is a very popular abrasive in modern lapidary owing to its durability and the relatively low cost of the material. It is, therefore, crucial to the art industry. In the manufacturing industry, this compound is used for its hardness in several abrasive machining processes such as honing, grinding, water-jet cutting, and sandblasting.

Comment on the hardness of silicon carbide

Silicon carbide has the ability to form an extremely hard ceramic substance making it useful for applications in automotive brakes and clutches, and also in bulletproof vests. In addition to retaining its strength at up to 1400°C, this ceramic exhibits the highest corrosion resistance among all the advanced ceramics.

Is silicon carbide soluble in water?

Silicon carbide is insoluble in water. However, it is soluble in molten alkalis (such as NaOH and  KOH) and also molten iron. Silicon carbide can be considered as an organosilicon compound.