Graphite and diamond are both made of carbon, but only one is good for pencil lead. Why is graphite useful for this task while diamond is not?

Question

Quizplus · Accepted Answer

The Answer is The carbon atoms in diamond are held together by covalent bonds; they share electrons so that each carbon atom has the noble gas configuration of eight electrons in its outermost electron shell and the bond strength in diamond is very strong. The carbon atoms in graphite are covalently bonded to form sheets, so the sheets are internally strong but are held together by weak van der Waals bonds.

Graphite and Diamond Are Both Made of Carbon, but Only