Advertisements
Advertisements
Question
Show that in a cubic close packed structure, eight tetrahedral voids are present per unit cell.
Advertisements
Solution
In ccp structure unit cell is divided into 8 small cubes. Each small cube has atoms at alternative corners [Figure]. In all, each small cube has 4 atoms. When joined to one another, they make a regular tetrahedron. Thus, there is one tetrahedral void in each small cube and 8 tetrahedral void in total. Each of the eight small cubes has one void in one unit cell of ccp structure. We know that ccp structure has four atoms per unit cell. Thus the number of tetrahedral voids is twice the number of atoms.
(a)
(b)
Again, the number of tetrahedral voids in ccp structure is equal to twice the total number of atoms.
APPEARS IN
RELATED QUESTIONS
What is the formula of a compound in which the element Y forms hcp lattice and atoms of X occupy 2/3rd of tetrahedral voids?
How will you distinguish between the following pair of terms?
Tetrahedral and octahedral voids
If the radius of the octahedral void is r and the radius of the atoms in close packing is R, derive the relation between r and R.
How many tetrahedral voids can exist per unit cell in a hexagonal close packing sphere?
The unit cell of a substance has cations A+ at the corners of the unit cell and the anions B− at the center. The simplest formula of the substance is ____________.
Total number of voids in 0.5 mole of a compound which forms hexagonal close packed structure is ____________.
A compound is formed by two elements A and B. The element B forms cubic close packing and atoms of A occupy `1/3"rd"` of tetrahedral voids. The formula of this compound is ____________.
What is the coordination number of sodium in Na2O?
Which set of following characteristics for ZnS crystal is correct?
Percentages of free space in cubic close packed structure and in the body-centered packed structure are respectively:
The number of octahedral voids present in a lattice is A. The number of closed packed articles, the number of tetrahedral voids generated is B the number of closed packed particles:
In the hexagonal close-packed structure of a metallic lattice, the number of nearest neighbours of a metallic atom is ____________.
If Germanium crystallises in the same way as diamond, then which of the following statement is not correct?
In which of the following arrangements octahedral voids are formed?
(i) hcp
(ii) bcc
(iii) simple cubic
(iv) fcc
The number of tetrahedral voids per unit cell in NaCl crystal is:
(i) 4
(ii) 8
(iii) twice the number of octahedral voids.
(iv) four times the number of octahedral voids.
In a compound, nitrogen atoms (N) make cubic close packed lattice and metal atoms (M) occupy one-third of the tetrahedral voids present. Determine the formula of the compound formed by M and N?
In which of the following structures coordination number for cations and anions in the packed structure will be same?
