Comparing Carbon-Carbon Bond in Graphite and Diamond

In this JC2 webinar we want to compare the bond energy of carbon-carbon bond in graphite and diamond.

The enthalpy of graphite is lower than that of diamond, which means that graphite is more stable than diamond.

This implies that the carbon-carbon bond in graphite is more stable than the carbon-carbon bond in diamond.

How is this possible if both are carbon-carbon single bonds?

Comparing Bond Energies using Hybridisation

Let's consider the state of hybridisation for carbon in graphite and diamond.

graphite and diamond deduce percentage s character

Carbon in graphite forms 3 sigma bonds with 3 other carbons hence it is sp2 hybridised. Its percentage s character is 1/3 or 33%.

Carbon in diamond forms 4 sigma bonds with 4 other carbons hence it is sp3 hybridised. Its percentage s character is 1/4 or 25%.

Since sp2 hybridised carbon in graphite has greater percentage s character, the sp2 orbitals will resemble more of s orbitals, hence it will be shorter and closer to the nucleus.

Therefore the corresponding bond formed from that shorter sp2 orbital will also be shorter and stronger.

So carbon-carbon bond in graphite will be more stable with a higher bond energy.

graphite and diamond sp2 carbon in graphite

Conversely, sp3 hybridised carbon in diamond has less s character, sp3 orbitals will resemble less of s orbital and more of p orbital, hence it will be longer and further away from the nucleus.

The corresponding bond formed from longer sp3 orbital will also be longer and weaker.

Hence carbon-carbon bond in diamond will be less stable with a lower bond energy.

graphite and diamond sp3 carbon in diamond

Topic: Introduction to Organic Chemistry, Organic Chemistry, A Level Chemistry, Singapore

Back to other previous Organic Chemistry Video Lessons.

Found this A Level Chemistry video useful?

This free chemistry video lesson is brought to you by Chemistry Guru, Singapore's trusted JC Chemistry tuition centre since 2010.

Please like this video and share it with your friends!

Join my 18,000 subscribers on my YouTube Channel for new A Level Chemistry video lessons every week.

Check out other A Level Chemistry Video Lessons here!

Need an experienced tutor to make Chemistry simpler for you?

Do consider signing up for my JC Chemistry Tuition classes at Bishan or on-demand video lessons!