Carbon dioxide and its special properties Carbon exists in the form of carbon dioxide including one oxygen atom and two carbon atoms. Carbon dioxide is collected in several ways. It is found in the gas eliminated from the volcanoes, when burning organic compounds and in the process of respiration of humans or animals. Plants consume carbon dioxide during photosynthesis and they can produce carbohydrate that is a substance such as sugar or starch that includes carbon, hydrogen and oxygen. Under minus 78 degrees, carbon dioxide condenses into white crystals. Dioxide carbon is a colorless gas doing harm to humans because carbonic acid will be formed when carbon dioxide combines with mucous membrane in nose and spit. So, if you take in carbon dioxide at high volume, you will feel stinging pain in nose and throat as well as a sour taste in mouth. Carbon dioxide is also a compound used for producing acid.