Graphite has h.c.p arrangements of carbon atoms and the parallel planes are 3.55 A˙ apart. Determine density of graphite :

In hcp alrangement total heighth = 4×23ras per given h2=223r=3.35 A˙ = 3.35×10-8cm.Volume of unit cell = 24 2r3= 24232×12×3.35×10-83= 2.93×10-22cm3Effective no. of atoms in hexagonal unit cell = 6∵density = 6×126.023×1023×2.93×10-22= 0.41 g/cc