Single Choice

Give the correct order of initials T (true) or F (False) for following statements: I. In an anti-fluorite structure, anions form FCC lattice and cations occupy all tetrahedral voids. II. If the radius of cations and anions are $$0.2\ \mathring A$$ and $$0.95\ \mathring A$$, then co-ordination number of cation in the crystal is $$4$$. III. An ion is transferred from a lattice site to an interstitial position in Frenkel defect. IV. Density of crystal always increases due to substitutional impurity defect.

ATFFF
BFTTF
CTFFT
DTFTF
Correct Answer

Solution

I. In an anti-flourite structure, anions form FCC lattice and cations occupy all tetrahedral voids.

II. Ratio of radius $$= \dfrac{0.2}{0.95} = 0.21$$ which lies between $$0.155-0.225$$ and so, it has co-ordination number of $$3$$.

III. Frenkel defect is a defect which is created when an ion leaves its appropriate site in the lattice and occupies an interstitial site. A hole or vacancy is thus produced in the lattice.

IV. The density of crystal may increase/decrease due to substitutional impurity defect.

Hence, the correct option is $$\text{D}$$

SIMILAR QUESTIONS

Solid State

Due to Frenkel defect, the density of ionic solids :

Solid State

Which of the following statement(s) for crystals having Frenkel defect is/are correct?

Solid State

The correct statement(s) regarding defects in solids is(are):

Solid State

Which of the following is a correct statement regarding defects in crystalline solids?

Solid State

Which among the following solids shows Frenkel defect?

Solid State

Frenkel defects are not found in alkali metal halide. Why?

Solid State

Density of a crystal decreases due to Schottky defect and remains constant due to Frankel defect. If true enter 1,else enter 0.

Solid State

Frenkel defect does not change the density of the ionic crystal whereas, Schottky defect lowers the density of ionic crystal. Give a reason.

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