Hydrocarbons and derivatives thereof mean that organic compounds contain carbon elements such as ethanol, acetic acid, and sucrose, and thus organic compounds are defined as carbon-containing compounds. Generally, organic compounds contain both carbon and hydrogen. From the structural point of view, hydrocarbons can be regarded as the precursor of organic compounds, while other organic compounds are regarded as hydrogen atoms in hydrocarbon molecules by other atoms. Or a derivative obtained by substituting a group, and therefore, an organic compound can also be defined as a hydrocarbon and a derivative thereof.

Therefore, organic chemistry is the study of the chemistry of carbon compounds, or the chemistry of hydrocarbons and their derivatives. Organic compounds are closely related to people's daily life such as clothing, food, housing, and transportation. The main ingredients of food are fat, protein and sugar, which are three important organic compounds; the main components of natural gas and petroleum are organic compounds.