Coordination number and number of carbon atoms per unit cell of diamond respectively are

In diamond each carbon atom is surrounded by four other carbon atoms. Unit cell of diamond contains 8 carbon atoms effectively.The co-ordination number of carbon in diamond is 4.It has F.C.C structure similar to ZnS.4 carbons occupy lattice sites while 4 carbons occupy alternate tetrahedral voids .Thus one unit cell of diamond has 8 carbon atoms.