Monday, 22 April 2013

Q 1.15: A compound forms hexagonal close−packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?



Q 1.15: A compound forms hexagonal close−packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?
Solution:
Number of atoms in close packaging = 0.5 mol
1 has 6.022 ×10 23  particles
So that
Number of close−packed particles
= 0.5 × 6.022 × 1023 = 3.011 × 1023
Number of tetrahedral voids = 2 × number of atoms in close packaging
Plug the values we get
Number of tetrahedral voids = 2 × 3.011 × 1023
                                                  = 6.022 × 1023
 Number of octahedral voids = number of atoms in close packaging
So that
Number of octahedral voids = 3.011 × 1023
Total number of voids = Tetrahedral void + octahedral void
                                       = 6.022 × 1023 + 3.011 × 1023 
                                       = 9.03 × 1023

8 comments:

  1. why is the voids in a hcp structure not called 'hexagonal' void rather than octahedral void?because its little confusing.please help

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    Replies
    1. its called octahedral due to the shape of the void.
      the void is similar to a octagon

      Delete
    2. It is called octahedral because around the void the arrangement of atom is octahedral. Shape of the void is not octahedral

      Delete
  2. In the above question they mentioned a compound so u cannot tell how many atoms are there. Then how can I assume it to be 6.023*10^23

    ReplyDelete
  3. I think each particle in above question is considered as an atom.so it can be assumed to be 6.022×10^23.

    ReplyDelete
  4. Qu ye duniya he..... Muze pats Nani and eska ans. de ke bata

    ReplyDelete