Giant Covalent Structure
Contents
Key Stage 4
Meaning
Giant covalent structures are very large molecules in which all the atoms are held to one another by covalent bonds.
About Giant Covalent Structures
- Giant covalent structures are molecules made of a large number of non-metal atoms joined by covalent bonds.
- The atoms in a giant covalent structure are arranged in a regular lattice (a repeating pattern of elements.
Examples
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| Diamond is a giant covalent structure where each Carbon atom has 4 bonds with adjacent atoms. | Graphite has a giant covalent structure where each Carbon atom has 3 bonds with adjacent atoms in a layer with loose bonds between the layers. | Graphene has a giant covalent structure where each Carbon atom has 3 bonds with adjacent atoms forming a layer that is one atom thick. | Silica is made of Silicon and Oxygen atoms in a lattice forming a giant covalent structure. |
Bulk Properties
- Giant Covalent Structures usually have very high melting points due to the strong chemical bonds between adjacent atoms.
- Giant Covalent Structures may have good or poor electrical conductors depending on whether there are any electrons free to move between atoms.
- Diamond is a poor electrical conductor because all the electrons are shared by adjacent atoms so none are free to move between atoms.
- Graphite and graphene are good electrical conductors because the Carbon atoms only form 3 bonds with adjacent atoms allowing a spare electron in each atom to move freely around the molecule.
References
AQA
- Giant covalent structures, page 118, GCSE Combined Science; The Revision Guide, CGP, AQA
- Giant covalent structures, page 33, GCSE Chemistry; The Revision Guide, CGP, AQA
- Giant covalent structures, pages 45, 48-51, GCSE Chemistry; Third Edition, Oxford University Press, AQA
- Giant covalent structures, pages 85-88, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
- Giant covalent structures, pages 87-90, GCSE Chemistry, CGP, AQA
- Giant covalent substances, page 44, GCSE Chemistry, Hodder, AQA
- Giant covalent substances, pages 159, 163-4, 247, GCSE Combined Science Trilogy 1, Hodder, AQA
- Giant covalent substances; properties of, page 160, GCSE Combined Science Trilogy 1, Hodder, AQA
Edexcel
- Giant covalent structures, page 24, GCSE Chemistry; The Revision Guide, CGP, Edexcel
- Giant covalent structures, page 87, GCSE Combined Science; The Revision Guide, CGP, Edexcel
- Giant covalent structures, pages 62-64, GCSE Chemistry, CGP, Edexcel