The Three Giant Covalent Structures You Must Know
Part of Giant Covalent Structures · GCSE GCSE Chemistry revision
This deep dive covers The Three Giant Covalent Structures You Must Know within Giant Covalent Structures for GCSE Chemistry. Revise Giant Covalent Structures in Bonding & Structure for GCSE Chemistry with 21 exam-style questions and 21 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 4 of 12 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 12
Practice
21 questions
Recall
21 flashcards
🔬 The Three Giant Covalent Structures You Must Know
Structure:
• Each carbon atom is bonded to 4 other carbon atoms
• Forms a rigid 3D tetrahedral structure
• ALL electrons are used in bonding — none are free
Properties:
• Very hard — used in cutting tools and drill bits
• Very high melting point (~3500°C) — many strong bonds to break
• Does NOT conduct electricity — no free electrons to carry charge
• Transparent — light can pass through the regular structure
Structure:
• Each carbon atom is bonded to only 3 other carbons
• Forms flat hexagonal layers (like chicken wire)
• One electron per carbon is NOT used in bonding — these are FREE
• Layers are held together by weak intermolecular forces
Properties:
• Soft and slippery — layers can slide over each other easily
• Very high melting point — still need to break covalent bonds within layers
• DOES conduct electricity — free electrons can move along the layers
• Black and opaque — free electrons absorb light
• Used in pencils (layers rub off) and as lubricant
Structure:
• Each silicon is bonded to 4 oxygen atoms
• Each oxygen is bonded to 2 silicon atoms
• Forms a giant 3D structure similar to diamond
Properties:
• Very hard — used in glass and sand
• Very high melting point (~1700°C)
• Does NOT conduct electricity — no free electrons
Fullerenes (C₆₀) and Graphene: These are carbon structures worth knowing! Fullerenes are hollow carbon "cages" that can carry drugs in medicine. Graphene is a single layer of graphite — incredibly strong and conducts electricity. Both appear in higher tier questions.
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Practice Questions for Giant Covalent Structures
Why do giant covalent structures have very high melting points?
Explain why graphite conducts electricity but diamond does not.
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