Other compounds, such as the pesticide DDT, may be life-threatening if humans and animals are exposed to large doses. Historically, as scientists tried to classify the bewildering array of carbon-based compounds, they made an important distinction between those they called organic compounds, and those called inorganic compounds. Chemicals like those based on petroleum, which are formed from living tissue, are by far the most numerous and are called organic chemicals. Because carbon compounds so greatly outnumber those made of any other element, it would be impossible to include examples of the majority of the compounds and their properties. Rather, this book will describe the main categories of carbon compounds and a few of the most common compounds.
Carbon compounds Carbon is very special because it can form so many compounds.
The explanation lies deep inside the atom. Carbon atoms can form strong links with four other atoms. This dramatically increases the number of patterns that carbon atoms can make. Carbon can also link together in long chains or rings, carbon to carbon to carbon to carbon and so on. And, quite unusually, these long chains cannot be destroyed by water or air or be attacked by bacteria.