1a)Suppose if CaO is added as an impurity to Li2O and CaCl2. In the first system

Question

1a)Suppose if CaO is added as an impurity to Li2O and CaCl2. In the first system, Ca ion
substitutes for Li ion and in the second, oxygen substitutes for Cl. What kind of defects
would you expect to form in these two systems? How many of these defects are
created for every ion added?

1b)In an ionic crystal like CaO, if you want to induce the formation of oxygen vacancies,
which would you introduce as substitutional impurities: cations with a higher positive
charge or lower positive charge than the cations in the parent structure? Explain your
choice.

Please explain the concept to me i have an examination to take next week.

Explanation / Answer

1 a)

metal excess defect when CaO is added as an impurity to Li2O because negative ions are missing from their lattice sites leaving holes in which the electrons remain entrapped to maintain the electrical neutrality which gives rise to Schottky Defect

metal deficiency defect when anions are in excess and may occupy interstitial positions .these are not common as anions are way too large for filling up the interstitial spaces

2)

if you want to induce the formation of oxygen vacancies, cations with a higher positive
charge are required because lower no of oxygen atoms are enough to balance the charge and rest are left as vacancies

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.