Is CS2 Nonpolar & Al2S3 Polar?

[cosmictide]

Hi guys,

I'm assuming that CS₂ is a nonpolar molecule and Al₂S₃ is a polar molecule. Would I be correct?

Thanks in advance.

 

[abitslow]

If there is a homework problem in back of this, please post there. Otherwise, please explain what you are basing your assumptions on, especially in the case of the aluminum compound. Unless you are speaking about exotic chemistry, assuming Al2S3 is a molecule is unjustified. In the solid state, Al occupies the tetrahedral holes of the HCP sulfide "ions", but may do this is a regular fashion, many allotropes are known.

 

[cosmictide]

If there is a homework problem in back of this, please post there. Otherwise, please explain what you are basing your assumptions on, especially in the case of the aluminum compound. Unless you are speaking about exotic chemistry, assuming Al2S3 is a molecule is unjustified. In the solid state, Al occupies the tetrahedral holes of the HCP sulfide "ions", but may do this is a regular fashion, many allotropes are known.

Thank you for your reply.

I'm just trying to figure out the intermolecular forces of the mentioned molecules. I'm guessing that the CS₂ molecule has a transient dipole since it's nonpolar and that Al₂S₃ forms a dipole-dipole force between molecules if it's a polar molecule. Any clarification would be great.

Thanks.

 

[Qube]

Molecules can have dipoles and yet be non-polar. For example, carbon dioxide has two permanent dipoles yet it is non-polar.

 

[Borek]

Al₂S₃ forms a dipole-dipole force between molecules if it's a polar molecule.

You were already told there is most likely no such thing as Al₂S₃ molecule.

Just like there is no NaCl molecule.

 

[cosmictide]

You were already told there is most likely no such thing as Al₂S₃ molecule.

Just like there is no NaCl molecule.

The question I was answering was concerned with the intermolecular forces between aluminium sulfide Al₂S₃ so I assumed such ionic compounds to exist. Thanks.

 

[Borek]

I assumed such ionic compounds to exist. Thanks.

Ionic compounds don't have typical molecules. This is what we are trying to tell you from the very first post.

 

[cosmictide]

Ionic compounds don't have typical molecules. This is what we are trying to tell you from the very first post.

Yes I understand. I should have used the term ionic compound from the beginning to avoid any confusion. Thanks.