Graphite
Graphite, archaically referred to as plumbago, is a crystalline form of the element carbon with its atoms arranged in a hexagonal structure. It occurs naturally in this form and is the most stable form of carbon under standard conditions. Under high pressures and temperatures it converts to diamond. Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels.
Graphite can exist as a black, slippery, hexagonal crystals. The carbon atoms in graphite form flat layers that are parallel, one above other, with weak inter molecular forces operating in-between the layers. The weak inter molecular forces allow movement of plain over each other.
Types of Graphite
- Flake graphite
- Amorphous graphite
- Lump/vein graphite
- High ordered pyrolytic graphite
Occurrence
Graphite occurs in metamorphic rocks as a result of the reduction of sedimentary carbon compounds during metamorphism. It also occurs in igneous rocks and in meteorites.
Properties of Graphite
- Graphite is an opaque, flaky, soft crystalline solid with metallic lustre.
- It is chemically in active and has high melting point but less dense than diamond.
- Unlike diamond, graphite is a good conductor of heat and electricity because of the presence of mobile electrons in the crystalline lattice.
- Graphite has one mobile electron out of four valent electrons because the remaining three are associated with bond formation.
- Graphite is non volatile and non sticky.
Uses of Graphite
- Graphite is used as a lubricant where normal lubricant could melt due to high temperature.
- Graphite mixed with clay is used to make lead pencil
- Graphite is used as electrode in electrolyte because of it's conductive property.
- It is used to line crucibles used for making high grade steel and in coating iron.
- It can be used as black pigment in paint.
- It is used as a neutron moderator in atomic piles.
Sources class notes, Wikipedia