There are several allotropic forms of carbon, right from diamond to carbon nanotube or buckytube. Allotropes are nothing but elements that exist in two or more different forms. The property of the chemical element existing in various forms is called allotropy.

Diamond, graphite, and amorphous carbon are the most common types of allotropes of carbon. From designing various ornaments to preparing pencils and lubricants, allotropes of carbon have a lot of importance in our day-to-day lives.

Here is a list of various allotropes of carbon:

• Diamond

• Graphite

• Lonsdaleite

• C60 (Buckminsterfullerene or Buckyball)

• Single-walled carbon nanotube or buckytube

Let us know in-depth about the above-mentioned allotropic forms of carbon.

#01 Graphite

The most stable form of carbon under standard conditions is nothing but graphite. When treated with high pressure and temperature, graphite gets converted to diamond. Graphite is mainly found in metameric stones, producing graphite by reducing the sedimented carbon during metamorphism.

Edward G. Acheson first discovered graphite in 1895. Graphite discovered in 1895 has been used as a pencil since 1565, which then became commercialized in the future years.

Structure of Graphite:

Occurrence: Occur in natural form or can be synthesized artificially.

Color: Grayish black and opaque.

Appearance: Crystalline solid, soft, and slippery to touch.

Density or weight: lighter or less dense than diamond.

Conductivity: It has good electrical and thermal conductivity.

Melting point: 4073 – 4173K

Solubility: Insoluble in polar and non-polar solvents.

Uses of Graphite

• Graphite is used in making pencils.

• As graphite has good conductivity, it is also used in electrodes.

• Used as a lubricant.

• Due to its heat tolerance, graphite is also used in refractories.

• Used in nuclear reactors.

• Used in the synthesis of graphene sheets.

#02 Diamond

Another allotrope of carbon that is the hardest and which has high heat conductance is the diamond with a hexagonal cubic lattice. Diamonds are naturally occurring carbon allotropes that can even be synthesized artificially.

There are mainly five types of diamonds: Type Ia, Type Ib, Type 1aB, Type IIa, and Type IIb. These are divided based on their nitrogen impurities. Type 1 diamonds have more nitrogen impurities, whereas Type 2 diamonds don’t have many types of nitrogen impurities.

Erasmus Jacobs first discovered diamonds between December 1866 and February 1867.

Structure of Diamond: 

Occurrence: Occurs in natural form or can be synthesized artificially.

Color: Yellow, brown, or gray, or it may even be colorless.

Appearance: Hard and solid.

Density: 3.51 g/cm³

Conductivity: High thermal conductivity and no electrical conductivity.

Melting point: 7280 Fahrenheit

Solubility: Insoluble in all types of solvents.

Uses of Diamond

• Diamonds are primarily used in the preparation of jewelry.

• It has good thermal conductivity and is most widely used in many industries.

• It is also used in automotive industries for the manufacturing of automobiles.

• Due to its hardness, it is also used in cutting hard substances.

• Also used in highway constructions.

#03 Lonsdaleite

Lonsdaleite is a hexagonal diamond that differs from the diamond by the presence of hexagonal lattice. Lonsdaleite is stronger than diamond. Meteorite debris is the natural source of this hexagonal diamond resulting from striking these meteors with the earth.

It was first discovered from the Canyon Diablo meteorite in 1967.

Structure of Lonsdaleite:

Occurrence: Found naturally in various meteorites.

Color: Crystals – Gray color

            Broken fragments – Pale yellow to brown color.

Appearance: very hard and transparent.

Density: 3.3 to 3.52 g/cm³

Conductivity: Good thermal conductivity and weak electrical conductivity.

Melting point: High melting point.

Uses of Lonsdaleite

• It is a marker of asteroidal impacts.

• Used in the manufacture of diamonds from graphite.

#04 Buckminsterfullerene

This is abbreviated as C60; as the name suggests, this has about 60 Carbon atoms. In 1985, scientists from the University of Sussex and Rice University discovered this. 

The scientists believed that there were only two allotropes, but in 1985 they found that there is another allotropic form of carbon and named it Buckminsterfullerene or C60.

Fullerenes are also seen in many other types like C70 is another example. 

Structure of Buckminsterfullerene: 

Occurrence: Small quantities of it can be found in soot. It also exists in space.

Color: Solutions of C60 have a deep purple color. 

Appearance: Black needle-like.

Density: 1.65 g/cm³

Conductivity: It is a non-conductor.

Melting Point: Near to 600 Celcius.

Uses of Buckminsterfullerene

• It is used as a catalyst.

• It is also used in specific drug delivery systems.

• It can be used as a surface coating.

# 05 Carbon Nanotubes

Nanotubes are a form of fullerene that are molecular-scale carbon tubes organized in layers similar to graphite. Carbon nanotubes, also known as buckytubes, are cylindrical carbon molecules with unique characteristics that might benefit many aspects.

Carbon nanotubes have an extremely high melting point because each carbon atom is connected to three other carbon atoms by strong covalent bonds.

Structure of Carbon Nanotubes:

Occurrence: These are human-made.

Color: Usually black.

Appearance: Carbon atoms as hexagonal structures.

Density: 1.3 to 1.4 g/cm3

Conductivity: They have high conductivity.

Melting Point: 3550°C

Uses of Carbon Nanotubes

• It can be used to store energy.

• Used in device modeling.

• It is used in the manufacturing of water filters. 

Conclusion

The above discussed five are the primarily seen allotropes of carbon atoms. Understanding the allotropes will give a good knowledge about the carbon and its properties.

As Carbon is the principle atom involved in organic chemistry, it is always necessary to understand this more better. Hope that this post was helpful. For more posts related to organic chemistry, you can bookmark this page and visit now and then.