Catenation is the phenomenon of linkage among atoms of the same element. This type of linking of identical atoms with one another' forming long chains or rings is possible only if the element is minimum bivalent.
1. Carbon is tetravalent and can form four covalent bonds. Carbon atom forms single bonds as well as double bonds and triple bonds with other carbon atoms.
Silicon also exhibits this property though to a lesser extent. The Si - Si bonds are not as stable as C - C bonds.
2. Carbon can form double and triple bonds. Silicon can form such bonds but they are very weak. Such compounds of silicon are very reactive and unstable.
3. Even siliconâsilicon pi bonds are possible. However, these bonds are less stable than the carbon analogues.
4. The size of silicon is larger than carbon, so due to steric hindrance silicon cant form long chains.
We hope that clarifies your query.