The number of octahedral void(s) per atom present in a cubic close-packed structure is [CBSE AIPMT 2012]a)2b)4c)1d)3Correct answer is option 'C'. Can you explain this answer?

Question

Accepted Answer

The total number of octahedral void(s) per atom present in a cubic close packed structure is 4. Besides the body centre, there is one octahedral void at the centre of each of the 12 edges. It is surrounded by six atoms, four belonging to the same unit cell (2 on the corners and 2 on face centres) and two belonging to two adjacent unit cells. Since each edge of the cube is shared between four adjacent unit cells, so is the octahedral void located on it. Only 1/4th of each void belongs to a particular unit cell. Thus, in cubic close packed structure, octahedral void at the body-centre of the cube is 1.
12 octahedral voids located at each edge and shared between four unit cells=

Total number of octahedral voids =4
We know that in ccp structure, each unit cell has 4 atoms. Thus, the number of octahedral voids is equal to 4/4=1.

Answer

ans is C
becoz there is 1 octahedral void in the centre and 1 on each edge center (which is shared by 4 atoms)
hence total no.of octahedral void =1+ 12*1/4 =4
total no. of atoms in ccp is 4
hence octahedral void per atom is 1

Answer

Answer - (b) :-no. of atoms(n) = no. of octahedral voids (n) CCP has 4 atoms so it has 4 octahedral voids

Answer

answer b hoga not c

Answer

Ans is not b: CCP is similar to Fcc so it has four atoms 1) 8 atoms at corner × ( 1/8) atom per unit cell =1 atom 2) 6 face centered atoms × (1/2) atom per unit cell = 3 atoms Therefore total no. Of atoms per unit cell = 4 atoms Octahedral voids = no. Of atoms Therefore no. Of octahedral voids = 4!! Tetrahedral voids = 2× no. Of atoms Therefore for Tetrahedral voids it is 8!! Conclusion; 4 and 8 respectively are no. Of voids for ccp/fcc (you can refer to page no 17 of NCERT text book for assurance) Thankyou

Top Courses for Class 12View all

Physics Class 12

English Class 12

English Flamingo Class 12

Chemistry Class 12

COMPUTER SCIENCE for Class 12(XII) - CBSE & NCERT Curriculum

Top Courses for Class 12

Top Courses for Class 12

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams