Carbon dating rock
The system of carbon allotropes spans a range of extremes: Atomic carbon is a very short-lived species and, therefore, carbon is stabilized in various multi-atomic structures with different molecular configurations called allotropes.
Graphite is much more reactive than diamond at standard conditions, despite being more thermodynamically stable, as its delocalised pi system is much more vulnerable to attack.Graphite is a good electrical conductor while diamond has a low electrical conductivity.Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials.At normal pressures, carbon takes the form of graphite, in which each atom is bonded trigonally to three others in a plane composed of fused hexagonal rings, just like those in aromatic hydrocarbons.The resulting network is 2-dimensional, and the resulting flat sheets are stacked and loosely bonded through weak van der Waals forces.At standard temperature and pressure, it resists all but the strongest oxidizers.
It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis.
The most common oxidation state of carbon in inorganic compounds is 4, while 2 is found in carbon monoxide and transition metal carbonyl complexes.
The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil, and methane clathrates.
At elevated temperatures, carbon reacts with oxygen to form carbon oxides, and will rob oxygen from metal oxides to leave the elemental metal.
This exothermic reaction is used in the iron and steel industry to smelt iron and to control the carbon content of steel: Carbon combines with some metals at high temperatures to form metallic carbides, such as the iron carbide cementite in steel, and tungsten carbide, widely used as an abrasive and for making hard tips for cutting tools.
Carbon forms a vast number of compounds, more than any other element, with almost ten million compounds described to date, The allotropes of carbon include graphite, one of the softest known substances, and diamond, the hardest naturally occurring substance.