Sn, C, Si and Ge are all group XIV elements. Yet, Sn is a conductor, C is an insulator while Si and Ge are semiconductors. Why ?
Carbon dosent exist in free state it always form some compound due to its tatravaleny and some of the allotropes like grapite the structure allows one free electron and thus conduct electrcity where silicon when heat very temperture it does but carbon allotrope diamond have pure carbon but the bond is so strong to be broken thus require very high temperature to conduct electricity