What distinguishes a crystal lattice from a unit cell?

In summary, a lattice is an idealized structure of crystals where each lattice point represents a group of identical atoms, also known as a basis. The unit cell is the smallest volume defined by a set of basis vectors, and is part of the lattice. It is the smallest representative part of the crystal structure with the same symmetry.
  • #1
asdf1
734
0
what's the difference between those two?
 
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  • #2
A lattice is a (idealized) structure of crystals where each lattice point represent an identical group of atoms. A group is sometimes called a basis. One can form basis vectors with which all lattice point positions can be expressed. The unit cell (I guess you mean the primitive cell) is the volume defined by the set of basis vectors. This is the smallest volume; there are no cells with smaller volumes.

Hopefully this was of help. If not, don't hesitate to ask. :smile:
 
  • #3
asdf1 said:
what's the difference between those two?
What does your textbook or class notes say ?
 
  • #4
my textbook says:
unit cell: crystal structure that's the smallest group of atoms possessing
the symmetry of the crystal
lattice: orderly array of points in space

so does that mean that the unit cell is part of the lattice?
 
  • #5
asdf1 said:
so does that mean that the unit cell is part of the lattice?
Yes, it is the smallest "representative" part.
 
  • #6
ok, thanks!
 

1. What is a crystal lattice?

A crystal lattice is a three-dimensional arrangement of atoms or molecules in a repeating pattern. It is the basic structural unit of a crystal and determines its physical properties.

2. What is a unit cell?

A unit cell is the smallest repeating unit within a crystal lattice, which when repeated in all directions, forms the entire crystal lattice. It is used to describe the overall structure of a crystal.

3. How do you determine the unit cell of a crystal?

The unit cell of a crystal can be determined using techniques such as X-ray crystallography or neutron diffraction. These methods involve analyzing the diffraction patterns produced by a crystal to determine its internal structure and unit cell dimensions.

4. What is the significance of crystal lattice and unit cell in material science?

The crystal lattice and unit cell play a crucial role in material science as they determine the physical and chemical properties of a material. The arrangement of atoms within a crystal lattice affects properties such as strength, conductivity, and optical properties, making it essential in understanding and designing new materials.

5. Can the unit cell of a crystal be changed?

The unit cell of a crystal cannot be changed as it is a fundamental property of the crystal. However, some materials may exhibit polymorphism, where they can form different crystal structures with different unit cells under varying conditions.

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