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Physical Chemistry – The Solid State-Concept of Crystals, Crystallography, Inter facial – part-4.

Physical Chemistry – The Solid State-Concept of Crystals, Crystallography, Inter facial – part-4.

https://www.gyanodhan.com/video/3B1.%20Class%2011%20and%2012%20IIT%20NEET/Chemistry/188.%20Physical%20Chemistry%20-%20The%20Solid%20State-Concept%20of%20Crystals%2C%20Crystallography%2C%20Inter%20facial%20-%20part-4.mp4

Here is a well-organized explanation of Physical Chemistry – The Solid State (Part-4), covering concepts of Crystals, Crystallography, and Interfacial Angles. This is perfect for Class 12 or undergraduate students:


Physical Chemistry – The Solid State

Part-4: Crystals, Crystallography, and Interfacial Angle


What is a Crystal?

A crystal is a solid in which the atoms, ions, or molecules are arranged in a definite and repeating pattern in three dimensions.

Example: Salt (NaCl), Quartz (SiOβ‚‚), Diamond, Sugar


Crystallography – The Science of Crystals

Crystallography is the branch of science that studies the geometry, structure, and properties of crystals.

Focus Areas:


Interfacial Angle – Definition

Interfacial angle is the angle between any two adjacent faces of a crystal.

Key Fact:

The interfacial angle is constant for all crystals of the same substance, regardless of size or shape.

This is called Steno’s Law (Law of Constancy of Interfacial Angles).


Types of Crystalline Solids (Recap):

Type Particles Involved Bond Type Examples
Ionic Crystals Ions Electrostatic NaCl, KCl
Covalent Crystals Atoms Covalent bonds Diamond, SiOβ‚‚
Molecular Crystals Molecules Van der Waals, H-bond Ice, COβ‚‚
Metallic Crystals Metal atoms Metallic bonding Fe, Cu, Zn

Crystalline vs Amorphous Solids

Feature Crystalline Solid Amorphous Solid
Particle Arrangement Regular, repeating Irregular, random
Sharp melting point Yes No
Long-range order Yes No
Example Quartz, NaCl, Diamond Glass, Plastic, Wax

Crystal Lattice and Unit Cell (Intro for Next Part)

You’ll learn more about:


Summary:

Crystals have a regular arrangement of particles and constant interfacial angles, which is studied under Crystallography. This regularity gives solids their specific shapes, properties, and behavior.


Would you like:

Let me know how you’d like to continue to Part 5!

Physical Chemistry – The Solid State-Concept of Crystals, Crystallography, Inter facial – part-4.

Solid state Notes.pdf

Laws of Crystallography and Crystal System

B.Sc. Sem. II,Chemistry,P.IV,5.Solid State