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

The Coordination no. of Y will be in the XY types of Crystal:

  1. 6

  2. 8

  3. 12

  4. 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In XY-type crystals (assuming AB-type like NaCl structure), if X has coordination number 6, then Y also has coordination number 6 due to the symmetrical nature of the structure. In NaCl-type crystals, each Na+ touches 6 Cl- and each Cl- touches 6 Na+.

Multiple choice

NaCl typecrystal (with coordination no.6 :6) can be converted into CsCl type crystal (with coordination no.8 :8)by apply

  1. High temperature

  2. High pressure

  3. High temperature and high pressure

  4. Low temperature and low pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Increasing pressure forces ions closer together, which favors a structure with a higher coordination number to maximize packing efficiency. Thus, NaCl (CN 6) converts to CsCl (CN 8) under high pressure.

Multiple choice chemistry matter in our surroundings diffusion in different states of matter properties of solids, liquid, and gas particle theory of matter

In an ionic solid, ${B}^{x-}$ ions constitute a ccp lattice, if ${A}^{y+}$ ion occupy $25$% of the tetrahedral voids, the possible ions in the solid are:

  1. ${A}^{+}$ and ${B}^{-}$
  2. ${A}^{2+}$ and ${B}^{4-}$
  3. ${A}^{2+}$ and ${B}^{-}$
  4. ${A}^{4+}$ and ${B}^{-}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the number of B ions be N. The number of tetrahedral voids is 2N. A ions occupy 25% of 2N, which is 0.5N. The ratio A:B is 0.5:1, or 1:2. To maintain charge neutrality, if B is -1, A must be +2. Thus, A is +2 and B is -1.

Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids

The lattice of a covalent crystal is composed of :

  1. atoms

  2. molecules

  3. ions

  4. compounds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A covalent network crystal consists of atoms at the lattice points of the crystal, with each atom being covalently bonded to its nearest neighbour atoms.


The covalently bonded network is three-dimensional and contains a very large number of atoms.

Examples of these crystals include graphite and diamond.
In these crystals, the atoms form covalent bonds with one another.
Multiple choice chemistry solid state classification of crystalline solids classification of solids introduction to solids
In a cubic structure of diamond which is made from X and Y, where X atoms are at the corners of the cube and Y at the face centres of the cube. The molecular formula of the compound is
  1. $X _2Y$
  2. $X _3Y$
  3. $XY _2$
  4. $XY _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a cubic unit cell, corner atoms (X) contribute 8 * (1/8) = 1 atom. Face-centered atoms (Y) contribute 6 * (1/2) = 3 atoms. The ratio of X to Y is 1:3, resulting in the formula XY3.

Multiple choice

The Miller indices of a crystal plane are represented by three integers, (h, k, l). What do these integers represent?

  1. The intercepts of the plane with the crystallographic axes

  2. The angles between the plane and the crystallographic axes

  3. The lengths of the edges of the unit cell

  4. The atomic positions within the unit cell
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Miller indices (h, k, l) represent the intercepts of the crystal plane with the crystallographic axes a, b, and c, respectively.

Multiple choice

In the context of crystallography, what is the term 'Bragg's Law' associated with?

  1. The relationship between the wavelength of X-rays and the diffraction angle

  2. The relationship between the energy of electrons and the diffraction angle

  3. The relationship between the temperature of a crystal and its lattice spacing

  4. The relationship between the pressure of a crystal and its lattice spacing
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bragg's Law describes the relationship between the wavelength of X-rays and the diffraction angle in X-ray crystallography.

Multiple choice

What is the basic repeating unit of a crystal lattice?

  1. Atom

  2. Molecule

  3. Unit cell

  4. Ion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A unit cell is the smallest repeating unit of a crystal lattice that retains the symmetry of the crystal.

Multiple choice

Which of the following is a type of crystal structure?

  1. Cubic

  2. Hexagonal

  3. Tetragonal

  4. Orthorhombic
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Cubic, hexagonal, tetragonal, and orthorhombic are all types of crystal structures.

Multiple choice

What is the Bravais lattice?

  1. A lattice with a repeating pattern of points

  2. A lattice with a repeating pattern of unit cells

  3. A lattice with a repeating pattern of atoms

  4. A lattice with a repeating pattern of molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Bravais lattice is a lattice with a repeating pattern of points that represent the positions of atoms or molecules in a crystal.

Multiple choice

Which of the following is a type of crystal lattice structure?

  1. Cubic

  2. Hexagonal

  3. Tetragonal

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cubic, hexagonal, and tetragonal are all types of crystal lattice structures, which are regular arrangements of atoms, molecules, or ions in a solid material.

Multiple choice

What is a stacking fault?

  1. A region of a crystal where the atoms are arranged in a different order than the rest of the crystal

  2. A boundary between two grains in a polycrystalline material

  3. A linear defect in a crystal where atoms are misaligned

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A stacking fault is a region of a crystal where the atoms are arranged in a different order than the rest of the crystal. It can be caused by the movement of atoms during crystal growth, or by the application of stress to a crystal.