One of the crystalline allotropes of elemental carbon.
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Molar mass: 12.011 g/mol
Melting point: 3,750 °C
Boiling point: 4,827 °C
Density: 2.26 g/cm³
Hardness: 1 (on the Mohs scale of mineral hardness)
Graphite is a dark grey, opaque material with a metallic shine. It is soft and leaves a mark on paper.
Each carbon atom is linked to three other carbon atoms by covalent bonds, forming hexagons. These rings form layers. The fourth electrons in the carbon atoms in the layer become shared and form an electron cloud. Due to its delocalised electron system, graphite conducts electricity and heat well. The layers are connected by weak secondary bonds, so they can slip easily.
Oxidants form graphitic acid, or graphite oxide, from graphite. Oxygen enters the space between the layers and causes graphite to swell.
Occurrence and production
Graphite occurs in areas prone to strong geological activity, where volcanic and sedimentary rock layers meet.
It is used in large quantities in the electrolysis phase of aluminium production as a carbon anode, as a graphite electrode in electric arc furnaces and in steel and corundum production. Pencils, crucibles and filters are also produced from graphite. Colloidal graphite (a permanent solution in oil or fat) is used as a lubricant.
The least tightly packed crystal structure.
Colourless, odourless, heavier-than-air gas. Necessary for the photosynthesis of plants.
Crystalline allotrope of elemental carbon, the hardest known natural substance.
The face-centred cubic metal lattice allows the closest fit of metal atoms.
A crystalline allotrope of carbon which was discovered at the end of the 1980s.
Metals forming hexagonal metallic lattices are rigid and difficult to machine.
The invention of the ballpoint pen made writing a lot easier.
A crystalline substance, an extremely important material in the electronics industry (semiconductors, integrated circuits).
A polymorphic compound, mostly found in the form of quartz.