Graphite and Diamond Are Made of the Same Thing

Graphite and diamond are polymorphs; both are made from carbon but have completely different properties and appearances because the carbon atoms are arranged differently within the two minerals (Figure). In diamond, each atom is covalently bonded to four others, creating a threedimensional(3D) network that has an equivalent properties altogether directions. In graphite, carbon atoms are covalently bonded to make sheets that contain interconnected 6-carbon rings; very weak van der Waals bonds hold the sheets together. As seen in Figure, diamond features a denser structure than graphite. the precise gravity of diamond is about 3.5, and graphite’s is 2.1 to 2.3.

Why does carbon have two natural polymorphs?The reason is that, at high pressures, dense minerals are thermodynamically more stable than less dense minerals. Graphite is one among many minerals, including quartz, that react to make more dense species when subjected to extreme pressure. Diamond is merely stable at the very high pressures reached quite 100 km (60 mi.) down within the Earth. At Earths’s surface it's metastable because it should.

The atomic arrangements in diamond and graphite.Because the atomic arrangements are so different, the 2 minerals have very different properties. Both minerals contain covalently bonded carbon atoms. In diamond, the bonding forms a 3 dimensional (3D) network. the general structure has very high symmetry, is extremely dense, and is extremely hard. Ingraphite, sheets of carbon atoms are held together by covalent bonds, but the sheets themselves are connected by weak van der Waals bonds (dashed lines). So, graphite is soft, deforms easily, and has excellent cleavage in one direction.