Carbon reacts with oxygen. When burned, carbon produces carbon dioxide and carbon monoxide. Carbon does not react with water, acids or other chemical compounds, but carbon atoms can unite with oxygen and hydrogen atoms to form refrigerants, solvents, lubricants and fossil fuels. It is the basis of organic chemistry.
Carbon has many different forms such as the graphite used in pencils, coal and diamonds. It is the sixth most common element in the universe and the second most common element in the human body. It occurs in minerals such as the carbonates of calcium and magnesium. Artificial diamonds can be created in a laboratory by subjecting pure carbon to extremely high pressure and temperatures.