1) What is coordination no of atoms :
 
A) IN A CUBIC CLOSE PACKED STRUCTURE
 
b) In abcc
 
2) A cubic solid is made of two elements P & Q . Atoms of Q are at the corners of the cube and P at the body centre.What is formula of the compound? What are the coordination no P & Q ?
 
3) If the radius of octahedral void is are r and radius of the atoms in close packing is R derive relation between r & R ?
 
4 ) Ferric oxide crystallise in a hexagonal close packed array of oxides ions with two out of every three octahedral holes occupied by ferric ions. derive the formula of ferric oxide.
 
5) Gold (atomic radius = 0.144 nm) crystallise in a ff centred unit cell.what is the length of a side of the cell ?
 
6) ALUMINIUM CRYSTALLISE IN A CUBIC CLOSE PACKED STRUCTURE . Its metallic radius is 125 pm
 
How many unit cells are there in 1.00 cm3 of aluminium ?
 
7) If NaCl is dopped with 10-3 mol % of SrCl2.what is the concentration of cation vacancies ?
 
 
 
 
 
 

Asked by pandeyknk | 29th Sep, 2014, 11:39: PM

Expert Answer:

Dear pandeyknk@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.

In case of multiple questions within a query, please post each question individually and let us know where you are getting stuck so that we would be able to explain things better.
 
 
Solution for your first query:
  1. The hexagonal closest packed (hcp) has a coordination number of 12 and contains 2 atoms per unit cell. The face-centered cubic (fcc) or cubic closed packed has a coordination number of 12 and contains 4 atoms per unit cell. The body-centered cubic (bcc) has a coordination number of 8 and contains 2 atoms per unit cell.
  2.  
 
Regards

Topperlearning Team.

Answered by Prachi Sawant | 30th Sep, 2014, 10:50: AM

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