[" 38.The co-ordination number of FCC structure for "],[" metals is "12," since "],[" (a) each atom touches "4" others in same plane,"3" in "],[" plane above and "3" in plane below."],[" ( ) each atom touches "4" others in same plane,"4" in "],[" plane above and "4" in plane below."],[" (c) each above and "3" in plane below."],[" plane above and "3" in plane below."],[" (d) each atom touches "3" others in same plane,"6" in "],[" lay plane er above and "6" in plane below."]