Question

Alkali halides do not show Frenkel defect because

• A. cations and anions have almost equal size
• B. there is a large difference in size of cations and anions
• C. cations and anions have low coordination number
• D. anions cannot be accommodated in voids

Hint:

In Alkali halides, the size of anions and cations is almost equal. 

Answer 1

The Correct Option is A

The correct answer is Option A) cations and anions have almost equal size

Frenkel defect occurs in compounds in which the size of anions and cations is different. In the Frenkel defect, the smaller ion comes to the interstitial place.

• In Alkali halides, the size of anions and cations is almost equal.
• Therefore, the ion size is large and they cannot get into the interstitial site.
• Hence, alkyl halide compounds do not show Frenkel defect.

Hence, Option "A" is the correct answer.

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Answer 2

The correct answer is Option A) cations and anions have almost equal size

Real Life Applications

• Many halogen-containing organic compounds may be found in nature, some of which are used in medicine.
• There are applications for these chemical classes in both daily life and business. They act as solvents for typically nonpolar molecules as well as raw materials for the synthesis of a wide range of chemical compounds.
• The antibiotic chloramphenicol, which is produced by soil bacteria and includes chlorine, is useful in treating typhoid fever.
• As potential surgical blood replacements, certain completely fluorinated compounds are being studied.
• They act as synthons' counterpoints in organic synthesis.
• They were actively used as refrigerants and propellants.
• Additionally, they are used in fire extinguishers.

Question can also be asked as

1. Why do alkali halides not have Frenkel defects?
2. What is the reason why Frenkel defects are not found in alkali halides?
3. What is the characteristic of alkali halides that prevents them from having Frenkel defects?
4. Why are Frenkel defects not possible in alkali halides?
5. What is the reason for the absence of Frenkel defects in alkali halides?

Answer 3

The correct answer is Option A) cations and anions have almost equal size

In compounds where the size of the cations and anions vary, the Frenkel defect is conceivable. 

• The smaller ion enters the interstitial space in this defect.
• The size of the cations and anions in alkali halides is almost equal.
• Due to this, they cannot enter the interstitial site due to their huge ion size.
• These compounds, therefore, do not exhibit the Frenkel defect.

Frenkel Defect Formation

• As the locations of molecules or atoms are established by the unit cell parameters in crystals at repeated set distances, defects are frequently seen in solid-state systems.
• Particle irradiation is typically used to engineer Frenkel flaws.
• The majority of a crystal's structure is flawed and unstable.
• The equilibrium in particle irradiation does not approach the detection limit because the enthalpy at the moment of creation is larger than it is at any other point. When the cation (smaller ion) is displaced in a structure, Frenkel defect can also happen by accident.

Characteristics of a Frenkel Defect

• In a Frenkel Defect, lattices form that are comparatively open.
• When the size of the cations is smaller than that of the anions, the Frenkel Defect develops.
• A solid-state in the Frenkel Defect has a low coordination number.
• The chemical makeup of material is unaffected by the Frenkel Defect.
• Frenkel Defect maintains the solid's mass and volume since it has no effect on the density of the structure.
• In the Frenkel Defect experiment, substances keep their electrical neutrality.

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