Diamond and graphite
A form (allotrope) of pure carbon in which all the atoms are bonded to four others in a giant tetrahedral network structure which is very strong. Diamond is the hardest known natural substance, has a very high melting point and does not conduct electricity. and A form of pure carbon in which all the atoms are bonded to three others in giant sheets which can slide over each other. are different forms of the A substance made of one type of atom only. carbon. They both consist of giant Giant regular arrangement of atoms, with a repeating pattern, held together by covalent bonds. structures of carbon The smallest part of an element that can exist., joined together by A bond between atoms formed when atoms share electrons to achieve a full outer shell of electrons.. However the shape of their structures and their The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. are different.
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Diamond
Structure and bonding
Diamond is a giant A covalent substance is a molecule containing one or more covalent bonds (shared pairs of electrons). substance in which:
- each carbon atom is joined to four other carbon atoms by covalent bonds
- the carbon atoms form a regular tetrahedral network structure
- there are no free Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons.
Properties and uses
The rigid network of carbon atoms, held together by strong covalent bonds, makes diamond very hard. This makes it useful for cutting tools, such as diamond-tipped glass cutters and oil rig drills.
Graphite
Structure and bonding
Graphite is a giant covalent substance in which:
- each carbon atom is joined to three other carbon atoms by covalent bonds
- the carbon atoms form a hexagonal layered network structure
- the layers have weak forces between them and can slide over each other
- each carbon atom has one un-bonded outer electron
- these un-bonded electrons are Electrons that are not associated with a particular atom, eg in a metal, outer electrons can be free to move through the solid., and are free to move
Properties and uses
Delocalised electrons are free to move through the structure of graphite, so graphite can To allow electricity, heat or other energy forms to pass through. electricity. This makes it useful for A conductor used to establish electrical contact with a circuit. The electrode attached to the negative terminal of a battery is called a negative electrode, or cathode. The electrode attached to the positive terminal of a battery is the positive electrode, or anode. in batteries and for electrolysis.
The layers in graphite can slide over each other because the forces between them are weak. This makes graphite slippery, so it is useful as a A lubricant is anything which reduces the friction between two surfaces..
More guides on this topic
- Formulae and equations - Edexcel
- Hazards and risks - Edexcel
- Atomic structure - Edexcel
- The periodic table - Edexcel
- Ionic compounds - Edexcel
- Simple molecular substances - Edexcel
- Metals and non-metals - Edexcel
- Calculations for all students - Edexcel
- Higher tier only calculations - Edexcel
- Sample exam questions - key concepts in chemistry - Edexcel