Dipole Moments

[Colin Bischof]

As a freshman college student in gen chem, we talk have talked about dipoles as more of a qualitative characteristic while the text book alludes to the idea that dipole moments have quantitative values. My quesiton is, what is the mathematical process to achieve such answers, for example:

CH₃Cl (chloroform?) has a dipole moment equal to 1.92 debeyes

ah maybe it has to do with the sums of the vectors created from difference of electronegativity?

[swansont]

The dipole moment depends on the charge and the separation distance (p = qd), so it would be related to the electronegativity and the size of the molecule.

 

https://en.wikipedia.org/wiki/Electric_dipole_moment

[Enthalpy]

The electron affinity does count, but not in a simple way. For instance the dipole moment of CO is small with 0.122D. So while it's a matter of charge and distance, predictions are difficult.

Experiment tells. Heavy software that computes molecular orbitals from first principles has a chance. I wouldn't trust too much estimation software that supposes additive rules on molecule subsets.