Molecular dipole moment?

In summary, Molecular dipole moments are created when there is a difference in electronegativity between the bonded atoms. Thus, electrons from one atom is attracted closer to the other causing one atom to become \delta+ and the other \delta-. Hope this helps.
  • #1
babbagee
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Molecular dipole moment?

What is a Molecular Dipole moment. My book explains it but i still don't get it. And here is a problem that ask me about it.

Which molecule in each pair has the greater dipole moment
a. SO2 or SO3
b. ICl or IF
c. SiF4 or SF4
d. H2O or H2S

Give the reason for your choice.

You only have to do one or two. After that ill get the point.

Thanks
 
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  • #2
A dipole moment is created when there is a difference in electronegativity between the bonded atoms. Thus, electrons from one atom is attracted closer to the other causing one atom to become [itex]\delta+[/itex] and the other [itex]\delta-[/itex]. Hope this helps.
 
  • #3
u should know the electronegative value and the shape/structure of the compound

for eg in SO3 u have planar triangular structure with angle 1200 so the dipoles which are vector quantity gets canceled and u have dipole moment=0

The direction of dipole moment is from + to - direction
 
  • #4
Intermolecular Force.

These are in order of strongest weakest, and the H bonding is only 5% as stong as an acutal bond.

1. Hydrogen Bonding (water molecules)
2. Dipole Moment (polar molecules)
3. London Forces (extremely week but interesting)

Nautica
 
  • #5
Man..what has Hydrogen Bonding to do with dipole?

See Dipole moment is donated by ::: u

And u can claculate net ""U"" of a compound by taking resultant of different u's of different bonds...

Like in SO3...calculate net "u" of SO SO SO ...as three O are bonded to single S... use parallelogram law vector method if u know the angle between the bonds...by knowing type of hybridization.
 
  • #6
Originally posted by Dr.Brain
Man..what has Hydrogen Bonding to do with dipole?

Has everything to do with it. They are both intermolecular forces which dictate melting points, boiling points, ect... I just figured you would like to know what they would be compared to, but I guess I was wrong.

Nautica
 
  • #7
Hi folk
May be anybody knows where I can found information (research articles) about transition dipole moments in quinone like molecules, especially in benzoquinone, phylloquinone , menaquinone. Someone told that these study already done, but I found nothing in search engines.

JPJ
 
  • #8
Hi JPJ, did you try: http://www.ncbi.nlm.nih.gov/PubMed it is where all the published peer-reviewed articles get collected.. usually they are biology oriented so it might not be found there though.. :S

Um.. otherwise I wouldn't know from the top of my head..
 
  • #9
Rajvirnijjar said:
What is a Molecular Dipole moment. My book explains it but i still don't get it. And here is a problem that ask me about it.

Which molecule in each pair has the greater dipole moment
a. SO2 or SO3
b. ICl or IF
c. SiF4 or SF4
d. H2O or H2S

Give the reason for your choice.

You only have to do one or two. After that ill get the point.

Thanks
If you have to draw out the Lewis structures for each of them, it will help you see it better at first, and then its all about the electronegativity.

Sorry this is a question of pure laziness but is SO2 linear bent, i just thought that that was the only way the problem would work since the SO3 has a zero dipole moment.
 
Last edited:
  • #10
Yeah, SO2 is linear bent, because of the lone pair.
 
  • #11
1. Hydrogen Bonding (water molecules)
2. Dipole Moment (polar molecules)
3. London Forces (extremely week but interesting)

Hydrogen bonding occurs in any molecule that has Hydrogen bonded with F, O, Cl and S too i belive.

A hydrogen bond can be thought of as a "super dipole" as it is just that; a dipole high strength dipole bond

In order to answer your question you must draw the lewis structures for all the atoms.

a) SO2 (it is non polar so contains dipole. the SO3 is polar)

b) IF (the attraction between I and F is stronger than I and Cl)

c) SF4 (again by drawing the lewis structures you can determine that SF4 is polar and SiF4 is not)

d) H20 (stronger dipole moment)
 

1. What is a molecular dipole moment?

A molecular dipole moment is a measure of the separation of positive and negative charges within a molecule. It is a vector quantity that indicates the overall polarity of a molecule.

2. How is molecular dipole moment calculated?

Molecular dipole moment is calculated by multiplying the distance between the positive and negative charges within a molecule by the magnitude of the charges. This value is then multiplied by the angle between the bond and the vector connecting the charges.

3. What factors affect the molecular dipole moment?

The molecular dipole moment is affected by the electronegativity of the atoms involved in the bond, the bond length, and the molecular geometry. The greater the difference in electronegativity between the atoms, the larger the dipole moment will be.

4. How is molecular dipole moment measured?

Molecular dipole moment is measured in units of Debye (D), which is equal to 3.33564 x 10^-30 coulomb-meters (C·m). It can be measured experimentally using techniques such as X-ray crystallography or spectroscopy.

5. What is the significance of molecular dipole moment?

The molecular dipole moment is important in determining the physical and chemical properties of a molecule. It affects the molecule's polarity, solubility, and reactivity. It also plays a role in intermolecular interactions and can influence the boiling point and melting point of a substance.

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