All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form.They are chemically resistant and require high temperature to react even with oxygen.At standard temperature and pressure, it resists all but the strongest oxidizers.
Although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature.
Carbon is the sixth element, with a ground-state electron configuration of 1s, of which the four outer electrons are valence electrons.
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.
For example, graphite is opaque and black while diamond is highly transparent.
Graphite is soft enough to form a streak on paper (hence its name, from the Greek verb "γράφειν" which means "to write"), while diamond is the hardest naturally occurring material known.Once considered exotic, fullerenes are nowadays commonly synthesized and used in research; they include buckyballs, The amorphous form is an assortment of carbon atoms in a non-crystalline, irregular, glassy state, not held in a crystalline macrostructure.It is present as a powder, and is the main constituent of substances such as charcoal, lampblack (soot) and activated carbon.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.