Allotropes of Carbon
Diamond, graphite, graphene and fullerenes are all pure carbon.
About this topic
Allotropes are different structural forms of the same element in the same state. Carbon has several: diamond, graphite, graphene, fullerenes such as buckminsterfullerene (C60) and carbon nanotubes. Their very different properties come from different bonding arrangements.
In diamond each carbon bonds to four others in a rigid tetrahedral lattice, making it the hardest natural substance, transparent and a poor conductor of electricity but a great conductor of heat. In graphite, each carbon bonds to three others in flat hexagonal layers with delocalised electrons between them, so it conducts electricity, is soft and slippery as layers slide, and is dark grey. Graphene is a single layer of graphite, about 200 times stronger than steel and extremely conductive. Fullerenes are hollow cages, C60 resembling a football with 12 pentagons and 20 hexagons; nanotubes are rolled-up sheets with exceptional strength. Amorphous carbon such as charcoal and soot has no long-range order.
Applications: diamond for cutting tools and jewellery, graphite for pencils, electrodes, lubricants and nuclear moderators, nanotubes for lightweight composites, and graphene for flexible electronics. Under high pressure and temperature graphite can be turned into synthetic diamond.
A misconception is that diamond is a different element from graphite. Both burn to give only carbon dioxide. Another is that pencil lead contains lead; it is graphite mixed with clay.
Key ideas
- Different bonding patterns
- Diamond is hard and insulating
- Graphene is one atom thick
Quick check
Use cases: where Allotropes of Carbon helps
- Homework: review the key idea behind Allotropes of Carbon before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Allotropes of Carbon without notes.
- Visual learning: play with the interactive lab to see how Allotropes of Carbon changes when you adjust its inputs.
- Teaching a friend: explain Allotropes of Carbon in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Allotropes of Carbon?
Diamond, graphite, graphene and fullerenes are all pure carbon.
What will I learn in Allotropes of Carbon?
Different bonding patterns. Diamond is hard and insulating. Graphene is one atom thick.
Is Allotropes of Carbon part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Allotropes of Carbon lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Allotropes of Carbon?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.