Chemistry

Solid State and Crystal Structures

151 Questions

Solid state chemistry focuses on the structural properties of crystalline solids. Questions cover Bravais lattices, unit cells, and close packed structures. This topic is essential for chemistry papers in UPSC and state PSC examinations.

Bravais lattice typesUnit cell calculationsClose packed structuresCrystal densityBragg's LawWurtzite structure

Solid State and Crystal Structures Questions

Multiple choice

Which of the following statements is/are correct?

  1. Each atom in hexagonal close packing has a coordination number 6.

  2. Solids may have tetrahedral or octahedral voids.

  3. The arrangement of atoms in fcc and bcc are the same.

  4. In a body centered cubic, the space occupied by spheres is 68%.

  5. Both 3 and 4.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because both the statements i.e. there is no difference between fcc and ccp arrangement and in body centered cubic and the space occupied by spheres is 68%, are true statements.

Multiple choice

Which of the following statements is/are not correct about halite structure?

  1. Cations occupy the lattice points of expanded fcc lattice and the anions occupy all the octahedral holes.
  2. The limiting radius ratio is in between 0.414 and 0.732.
  3. The coordination numbers of cation and anion are 4 and 8 respectively.
  4. The general formula of ionic compounds having halite structure is AB.

  1. 1 and 2

  2. 1 and 3

  3. 1 and 4

  4. 2 and 3

  5. 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In halite or rock-salt structure, anions occupy the lattice points of expanded face centred cubic lattice and the cations occupy all the octahedral holes. The limiting radius ratio is in between 0.414 and 0.732. The co-ordination numbers for both cation and anion is 6:6. The general formula of ionic compounds having this structure is AB. Examples: NaCl, KCl, MgO, CaO etc.

Multiple choice

Which of the following statements is not correct regarding the bcc system?

  1. Packing efficiency of BCC lattice structure is 74%.
  2. HCP and BCC lattice structures have same packing efficiency.
  3. Coordination number of atoms in BCC crystal lattice is 8.

  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Packing efficiency in HCP lattice is 74%. Packing efficiency of BCC lattice structure is 68%. HCP and BCC lattice structures have different packing efficiency. Thus, this option is correct.  

Multiple choice

Atoms of element B form hcp lattice and those of the element A occupy 2/3rd of tetrahedral voids. What is the formula of the compound formed by the elements A and B?

  1. A3B4

  2. A4B3

  3. A2B3

  4. A3B2

  5. AB
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The number of tetrahedral voids formed is equal to twice the number of atoms of element B and only 2/3rd of these are occupied by the atoms of element A. Hence, the ratio of the number of atoms of A and B is 2 × (2/3):1 or 4:3 and the formula of the compound is A4B3.

Multiple choice

In cubic closed pack structure of mixed oxides, the lattice is made up of oxide ions, one eighth of the octahedral voids are occupied by divalent ions (A2+), while one half of the octahedral voids are occupied by trivalent ions (B3+). The formula for the oxide is

  1. A3B2O4

  2. A2B2O4

  3. AB2O4

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  Let the number of oxides be = x So number of octahedral  voids = x And number of tetrahedral voids = 2x Number of A2+ ion = 2x/8 = x/4 Number of B3+ ions = x/2 A2+ : B3+ : O2- x/4: x/2: x 1:2:4 Hence the formula for the oxide is AB2O4