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how many n where r the tetrahedral voids located in hexagonal close packing

how many n where r the tetrahedral voids located in  hexagonal close packing

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3 Answers

SAGAR SINGH - IIT DELHI
878 Points
13 years ago

Dear student,

The close packed structures have both octahedral and tetrahedral voids. In a ccp structure, there is 1 octahedral void in the centre of the body and 12 octahedral void on the edges. Each one of which is common to four other unit cells. Thus, in cubic close packed structure.

 

Octahedral voids in the centre of the cube =1

 

Effective number of octahedral voids located at the 12 edge of = 12 × 1/4 = 3 

 

Total number of octahedral voids = 4

 

In ccp structure, there are 8 tetrahedral voids. In close packed structure, there are eight spheres in the corners of the unit cell and each sphere is in contact with three groups giving rise to eight tetrahedral voids

 

 

                  416_tetrahedral.JPG

 

                      436_octahedral.JPG
 

Circles labelled T represent the centers of the tetrahedral interstices in the ccp arrangement of anions.  The unit cell "owns" 8 tetrahedral sites.

 

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Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

 

Circles labelled O represent centers of the octahedral interstices in the ccp arrangement of anions (fcc unit cell).  The cell "owns" 4 octahedral sites.

 

Kanwar Gaurav
33 Points
12 years ago

sir, i want to know clear diagrametically location of tetrahedral & octahedral voids in hcp structure??

ankit singh
askIITians Faculty 614 Points
3 years ago
in fcc 8 tetrahedral voids are present ,now
 

Dear student,

The close packed structures have both octahedral and tetrahedral voids. In a ccp structure, there is 1 octahedral void in the centre of the body and 12 octahedral void on the edges. Each one of which is common to four other unit cells. Thus, in cubic close packed structure.

 

Octahedral voids in the centre of the cube =1

 

Effective number of octahedral voids located at the 12 edge of = 12 × 1/4 = 3 

 

Total number of octahedral voids = 4

 

In ccp structure, there are 8 tetrahedral voids. In close packed structure, there are eight spheres in the corners of the unit cell and each sphere is in contact with three groups giving rise to eight tetrahedral voids

 
dear student

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