Giant Structures
Diamond, graphite and silica are giant covalent structures.
About this topic
Giant covalent structures have atoms bonded in a continuous network by strong covalent bonds. Diamond, where each carbon bonds to four others, is extremely hard; graphite has layers with delocalised electrons that conduct and slide easily; silicon dioxide forms quartz and sand. They have very high melting points and are generally insoluble.
Melting a giant covalent substance means breaking many strong covalent bonds, which takes enormous energy; diamond does not melt until around 3500 degrees Celsius. Diamond has no free electrons, so it is an insulator, but its rigid tetrahedral network makes it the hardest natural material, used in drill bits and cutting tools. In graphite, each carbon bonds to three others in hexagonal sheets, leaving one delocalised electron per atom, with only weak forces between layers, which makes it soft, slippery and a conductor. Compare these with giant ionic lattices and giant metallic structures, which are also high melting.
Graphite is used in pencils, lubricants and electrodes, silicon forms computer chips, and silicon dioxide is the basis of glass. Graphene, a single layer of graphite, is extremely strong and conductive.
A misconception is that graphite and diamond are different elements; both are carbon, differing only in structure. Also, giant structures are not molecules, so they have no formula for a single unit, only the simplest ratio of atoms.
Key ideas
- Diamond is hard, graphite conducts
- Silica is sand
- Graphene is a single layer
Quick check
Use cases: where Giant Structures helps
- Homework: review the key idea behind Giant Structures before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Giant Structures without notes.
- Visual learning: play with the interactive lab to see how Giant Structures changes when you adjust its inputs.
- Teaching a friend: explain Giant Structures 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 Giant Structures?
Diamond, graphite and silica are giant covalent structures.
What will I learn in Giant Structures?
Diamond is hard, graphite conducts. Silica is sand. Graphene is a single layer.
Is Giant Structures 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 Giant Structures 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 Giant Structures?
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.