Organic compounds: there are many kinds and huge quantities (more than 30 million kinds are known, and they are increasing at a rate of one million every year).

But there are few elements such as C, H, O, N, P, S, X (halogen: F, Cl, Br, I).

Bonding characteristics of carbon atoms in organic compounds 1.

There are four electrons in the outermost layer of carbon atoms, so it is not easy to lose or gain electrons to form cations or anions. Carbon atoms form valence compounds with nonmetals such as hydrogen, oxygen, nitrogen, sulfur and phosphorus through valence bonds.

Due to the bonding characteristics of carbon atoms, each carbon atom can not only form four valence bonds with hydrogen atoms or other atoms, but also combine with each other through valence bonds. Carbon atoms can form not only stable single bonds, but also stable double bonds or triple bonds. Multiple carbon atoms can be combined with each other to form short carbon chains, short carbon chains can also be branched or combined into carbon rings, and carbon chains and carbon rings can also be combined with each other. Therefore, molecules containing the same atom and the same number of each atom may have many different ways of atom combination, forming molecules with different structures.

2. Isomerization of organic compounds

The compounds have the same molecular formula, but different structures, so their properties are different. This phenomenon is called heterogeneity. Isomeric compounds are isomers. In organic compounds, when the number of carbon atoms increases, the number of isomers also increases. Isomers are very common in organic compounds, which is one of the reasons why there are so many organic compounds in nature.