- #1
asdf1
- 734
- 0
what's the difference between those two?
What distinguishes a crystal lattice from a unit cell?
Click For Summary
Discussion Overview
The discussion centers on the distinction between a crystal lattice and a unit cell, exploring definitions and relationships within the context of crystallography.
Discussion Character
- Conceptual clarification
Main Points Raised
- One participant defines a lattice as an idealized structure of crystals where each lattice point represents an identical group of atoms, referred to as a basis.
- Another participant describes the unit cell as the smallest group of atoms that possesses the symmetry of the crystal, suggesting it is a specific volume defined by basis vectors.
- A later reply confirms that the unit cell can be considered the smallest representative part of the lattice.
- There is a request for clarification regarding textbook definitions and interpretations of the terms.
Areas of Agreement / Disagreement
Participants generally agree on the definitions of lattice and unit cell, with some clarification needed on their relationship. However, the discussion does not reach a consensus on the nuances of these definitions.
Contextual Notes
Some definitions may depend on specific contexts or interpretations, and there is a lack of consensus on the terminology used in different educational resources.
- #2
assyrian_77
- 115
- 0
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.
Hopefully this was of help. If not, don't hesitate to ask.
- #3
Gokul43201
Staff Emeritus
Science Advisor
Gold Member
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What does your textbook or class notes say ?asdf1 said:
- #4
asdf1
- 734
- 0
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?
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
Gokul43201
Staff Emeritus
Science Advisor
Gold Member
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Yes, it is the smallest "representative" part.asdf1 said:
- #6
asdf1
- 734
- 0
ok, thanks!
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