Giant covalent structure
A huge network of atoms joined by strong covalent bonds. These substances have very high melting points.
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Analogy
It is like a giant net in which every knot is tied tight to its neighbours.
In practice
Diamond, graphite and silicon dioxide (sand) are giant covalent structures.
Practice
Flashcards
- Why does graphite conduct electricity?Each carbon atom has a free electron that can move through the layers.
Interview questions
- Explain why diamond is very hard but graphite is soft, even though both are made only of carbon.
- Diamond: each carbon bonded to four others
- Strong covalent bonds in all directions
- Graphite: each carbon bonded to three others in layers
- Weak forces between layers let them slide
Questions people ask
Why does silicon dioxide have a high melting point?
Silicon dioxide, the main substance in sand, is a giant network of silicon and oxygen atoms. Each atom is held by strong covalent bonds in all directions. Melting needs many of these bonds to break, which takes a great deal of energy. It melts at over 1,600 degrees Celsius.
What is diamond used for?
Diamond is the hardest natural substance, so it is used to cut and grind. Drill bits and saw blades are tipped with it. It is also used in jewellery because it is clear and sparkles. Its strong covalent bonds in every direction give this hardness.