14.6. (a) What are the essential similarities and differences in the plastic deformation of metals, ionic solids, and covalent solids? (b) Assuming hardness characteristics are related to plasticity as well as bond strength, would you predict a hexagonal modification of SIC to be harder or softer than a cubic modification? Why?

At 23° K, the crystal structure transforms from BCC to HCP keeping density same. The 0 cubic face in BCC is a = 3.42 A and in HCP is == 1.53. The lattice constant in HCP a structure is, 0 (a) 2.64 A 0 (b) 3.16 A 0 (c) 2.16 A 0 (d) 2.42 A

Solve it correctly please. I will rate and review accordingly,

Germanium is a semiconductor. With the aid of diagrams showing bands of molecular orbital, explain why it is a poor conductor and how doping it with phosphorus increases its conductivity.