The Solid State

The statement that is INCORRECT about the interstitial compounds is :

• they are chemically reactive

• they have metallic conductivity

• they have high melting points

• they are very hard

Consider the bcc unit cells of the solids 1 and 2 with the position of atoms as shown below. The radius of atom B is twice that of atom A. The unit cell edge length is 50% more in solid 2 than in 1. What is the approximate packing efficiency in solid 2?

• 75%

• 65%

• 45%

• 90%