Diamond, graphite, graphene, fullerenes and nanotubes are different structural forms of carbon.
Practise Bonding & Molecular Structure All Bonding & Molecular Structure topics
Allotropes are different structural forms of the same element in the same physical state. Carbon has many allotropes whose properties differ dramatically because the bonding dimensionality and hybridization change from one form to another. Diamond has an sp3 three-dimensional network, graphite has sp2 layers, graphene is a single layer of graphite, fullerenes are closed cages and carbon nanotubes are rolled sheets. Amorphous carbon has no long-range order. The same element can therefore form very hard, very soft, insulating and conducting materials.
Key ideas: Compare quickly: diamond sp3, density 3.51 g/cm3, insulator; graphite sp2, density 2.26 g/cm3, conductor within layers; graphene single layer; C60 molecular with 60 atoms and sp2 carbons slightly pyramidalized; nanotubes rolled graphene. Graphite is slightly more stable than diamond at standard conditions, by 2 kJ/mol, and diamond forms at high pressure.
Common mistakes and connections: Students say diamond is the most stable form of carbon (it is metastable under ambient conditions, but conversion is extremely slow), or confuse allotropes with isotopes. Another error is thinking graphene and graphite differ in chemical composition. Links to hybridization, network solids, nanotechnology and thermodynamic stability.
Same element, different bonding: dense, 3D tetrahedral diamond versus layered graphite and open-cage fullerite, all made only of carbon. The interactive lesson shows this as a live animation or chart.
Diamond is an electrical insulator, whereas graphite is a good electrical conductor, although both are pure carbon.
Diamond, graphite, graphene, fullerenes and nanotubes are different structural forms of carbon.
Allotropes of Carbon is a intermediate topic in Bonding & Molecular Structure. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Bonding & Molecular Structure first: Molecular Solids, Ionic Solids, Metallic Solids.
The next topics in Bonding & Molecular Structure are Graphite Structure and Diamond Structure.
Yes. The interactive lesson includes a self-check question on Allotropes of Carbon, and the Bonding & Molecular Structure quiz draws on every topic in this area.
Allotropes of Carbon is topic 83 of 104 in Bonding & Molecular Structure.