Is NaCl Ferroelectric Due to Its Lattice Polarization?

[minifizicus]

Why NaCl is not ferroelectric? What is the physical explanation?

 

[mjc123]

Why should it be? What is the cause of ferroelectricity?
Look at the table of crystal classes in the article https://en.wikipedia.org/wiki/Ferroelectricity
Where does NaCl belong in that table?

 

[minifizicus]

You don't understand my question...I know , NaCl is not ferroelectric, but every thing have a explanation. For example, a crystal is not ferroelectric if the center of positive and center of negative charge are the same. So, this is the explanation for NaCl? the center of positive and center of negative charge are the same? or it's another explanation?

 

[mjc123]

Well, are the centre of positive and negative charge the same?
You do know the crystal structure of NaCl, don't you?

 

[Lord Jestocost]

NaCl is not ferroelectric, but every thing have a explanation.

As said above, only certain materials exhibit ferroelectric behavior in particular temperature ranges. If you allow an elementary picture: In such materials, the lattice polarization can produce a local field which tends to stabilize the polarization further. Whether this feedback process occurs or not depends on the size of the material’s polarizability. Thus, only in specific materials spontaneous lattice polarization can arise in the absence of an applied electric field.
Some basic concepts are treated in:
The Feynman Lectures on Physics Vol. II Ch. 11: Inside Dielectrics