text: do we have an example of a silicon based life form?   no we do not have any living examples. why? the answer lies in the ability to catenate.  silicon does not share the property of being able to catenate (ability to bond to itself) like carbon. the si-si bond is weaker compared to the c-c bond. so you find less si is a less versatile atom. also si does not form pi-bonds as easily as carbon does. si has a negligible pi-bond overlap compared to c, most probably si has a larger atomic radius than c, so the pi-bond overlap is less strongly held to the nucleus and hence is a weak bond.