question_answer 28)

(a) What is meant by the term 'coordination number'? (b) What is the coordination number of atoms: (i) in a cubic close packed structure? (ii) in a body centred cubic structure ?  

Answer:

(a) Coordination number is the number of spheres which are touching a particular sphere. In ionic crystals, it is the number of oppositely charged ions surroundings a particular ion. (b) (i) Twelve (ii) Eight.