What do you understand by catenation?
Catenation - The atoms of some elements (such as carbon) can link with one another through strong covalent bonds to form long chains or branches. This property is known as catenation. It is most common in carbon and quite significant in Si and S.
Catenation: The property to form chains or rings not only with single bonds but also with multiple bonds with itself is called catenation
For example, carbon forms chains with (C-C) single bonds and also with multiple bonds (C = C or C = C).