Carbon

Graphite reacts with the oxidizing acid hot concentrated nitric acid to form mellitic acid, C₆(COOH)₆.

Carbon, as graphite, burns, forming gaseous carbon oxides. Diamond, when heated to 600-800 °C, also burns, forming gaseous carbon oxides.

At sufficient amounts of O₂, carbon forms CO₂ (carbon dioxide). This is called complete combustion [5]:

C(s) + O₂(g) CO₂(g)

At insufficient amounts of O₂, carbon forms CO (carbon monoxide). This is called incomplete combustion [5]:

2 C(s) + O₂(g) 2 CO(g)

Carbon reacts with calcium oxide at high temperatures, forming calcium carbide [5]:

3 C(s) + CaO(s) CaC₂(s) + CO(g)

Graphite reacts with fluorine, F₂, (excess amount) at high temperatures, forming a mixture of CF₄, C₂F₆ and C₅F₁₂.

C(s) + F₂(g) CF₄(g) + C₂F₆ + C₅F₁₂

At room temperatur, the reaction with fluorine result in a mixture called "graphite fluoride". This is a non-stoichiometric mixture with the formula CF_x (0.68 < x < 1). The compound is black when x is low, silvery at x = 0.9 and colourless when x is around 1.

Carbon reacts with sodium amide at 500-600 °C, forming sodium cyanide [5]:

C(s) + NaNH₂(g) NaCN(s) + H₂(l)

Carbon reacts with sulfur at high temperatures, in the absense of oxygen, forming carbon disulfide [5]:

C(s) + 2 S(s) CS₂(g)

Carbon, either as graphite or diamond, does not react with water under normal conditions.

At high temperatures, when water is blown through hot coke, carbon will react with water, forming a mixture of hydrogen (H₂, 50%), carbon monoxide (CO, 40%), carbon dioxide (CO₂, 5%), nitrogen and methane (N₂ + CH₄, 5%).

2 C(s) + 3 H₂O(g) CO(g) + CO₂(g) + 3 H₂(g)