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HETAV PATEL

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What is the difference between hcp and ccp packing??

What is the difference between hcp and ccp packing??

Grade:12

3 Answers

SAHIL
3778 Points
7 years ago
  1. Covering the tetrahedral voids: Here, tetrahedral voids of the second layer may be covered by the spheres of the third layer. It gives rise to ABABAB… type pattern. The three-dimensional structure is called hexagonal close-packed structure.  Examples: Mg, Zn
  2. Covering the octahedral voids: Here, octahedral voids of the second layer may be covered by the spheres of the third layer. It gives rise to ABCABCABC… type pattern. The three-dimensional structure is called cubic close-packed structure or face-centred cubic structure.  Examples: Cu, Ag
  3. thanks and approve my answer
  4. if still not understand please post
  5. regards sahil
Shreyas Patil
131 Points
7 years ago
U
Umakant biswal
5349 Points
7 years ago
@ shreyas 
there are a small besic diffrence between the two types of packing , i am explaining that below . 
HCP (HEXAGONAL CLOSE PACKING ) 
1- HERE , the third layer of sphere are exactly identical with the first layer of sphere . that means the spheres are alligned in ABAB PATTERN , TAKE A AS FRST LAYER SPHERE ARRENGEMENT , AND B AS THE 2ND LAYER SPHERE ARRENGEMENT . 
2- IT COVERS THE TETRAHEDRAL VOID , TETRAHEDRAL VOID ARE THE FALSE VOIDS . THAT WILL GENERATE IF THE SPHERE WILL ALLIGN ON THE NEXT LAYER OF VOID . 
3- ITS ONE OF THE IDEAL WAY OF PACKING , AND THE PACKING FRACTION IS APPROXIMATELY 74 PERCENT . 
CCP (CUBIC CLOSE PACKING ) 
1-HERE , the fourth layer sphere are same as that of the frst layer , the same sequence , take A as frst layer arrengement , B as 2nd layer arrengement , and C as 3rd layer arrengement . 
2- its represented by ABCABC TYPE , (REASON EXPLAINED ABOVE ) 
3- IT will cover the octahedral voids , the octahedral voids are the true voids , and these will be generate when a void will overlap with anathor void , 
(REMEMBER ITS DIFFRENT FROM TETRAHEDRAL , IN TETRAHEDRAL WE HAVE SPHERE OVERLAPPING A VOID)
4- ITS the less efficient packing than hcp one , with approx 68 percent packing efficiency .. 
HOPE IT CLEARS YOUR DOUBT 
ALL THE BEST .. 

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