Why is carbon chemistry so varied?
Carbon chemistry is so varied because carbon can form bonds to four other atoms.
Carbon can form chemical bonds with four other atoms.
This enables it to form a huge number of compounds with many different arrangements of atoms. Nearly ten million compounds contain carbon. There are more compounds of carbon than of all the other elements put together.
A carbon chain can link to many other elements.
Thousands of molecules are possible using just carbon and hydrogen. When oxygen, nitrogen, calcium, phosphorus, and sulfur are included, the number rises to tens of millions.
Carbon can form double bonds and triple bonds as well as single bonds.
Inserting C=C and C≡C bonds into a chain increases the number of compounds. It also changes their chemical properties. When carbon is bonded to other atoms by double bonds (e.g., C=O) or triple bonds (e.g., C≡N), we get functional groups. Functional groups determine the many different chemical reactions of carbon compounds.
Carbon is unique. Other elements have some of the above properties. No other element has all of them. That is why carbon chemistry is so varied.