Questions tagged [dipole]

For questions about the dipole moment of a bond or a molecule; its calculation, comparison with other bonds or molecules, affect on molecular properties, etc.

25 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
15
votes
0answers
2k views

How to Calculate Transition Dipole Moment from Two Known Wavefunctions

I am interested in calculating the transition dipole moment (TDM) from the information from two wavefunctions of different states. This is somewhat similar to calculating the molecular dipole moment ...
5
votes
0answers
76 views

Program to compute multipoles of water at CCSD(T)-F12 accuracy

I want to compute traceless cartesian electrostatic multipole moment tensors up to fourth order (hexadecapole), at CCSD(T)-F12 accuracy using a large basis set. I'd like to be able to choose the ...
3
votes
0answers
46 views

Why is there only little difference between molecular dipole moments in CHX3 compounds (X = Cl, Br, I)?

Why is there only little difference between molecular dipole moments in $\ce{CHX3}$ compounds ($\ce{X}$ = $\ce{Cl}$, $\ce{Br}$, $\ce{I}$)? As we can see there is a huge difference in dipole moment of ...
2
votes
0answers
39 views

Do I understand correctly that simulation volume influences relative permittivity calculations? If so, how is the result useful?

I am having a lot of trouble understanding the influence of volume on relative permittivity/static dielectric constant. I'm not a chemist, but am using molecular dynamics to calculate relative ...
2
votes
0answers
33 views

Perturbation theory for molecules, chromophore group, dipole approximation,

I am interesting in chromophore group and dipole approximation. For example, i have a molecule (acetone or any other ketone/enol) which is belongs to some symmetry group. Because of the symmetry ...
2
votes
0answers
146 views

For a given period, why is the boiling point of the halogen greater than that of the noble gas?

The boiling point of bromine, a halogen, is $\pu{58.8^\circ C}$, while the boiling point of krypton, the noble gas in the same period as bromine, is $\pu{-153.4 ^\circ C}$. I thought that the larger ...
2
votes
0answers
476 views

What is the need for dipole moment if electronegativity already exists?

Say we have an HCl molecule. The difference in electronegativities of the H and Cl atoms tells us how polar the HCl molecule is. The dipole moment is also a measure of the degree of polarity in ...
2
votes
0answers
3k views

Lone pair and dipole moment of ozone

(This is a question similar to this and this, but none of the answers to those two questions answer my question.) I've seen many places explain the dipole moment of ozone from the formal charges of ...
2
votes
0answers
1k views

Which has more ionic character, LiF or K2O?

After drawing the structures of both and considering dipole moment, doesn't it seems that all K2O should have more ionic character than LiF? My textbook says its LiF.
2
votes
0answers
30 views

How does hot air remove guests from cyclodextrin?

Cyclodextrin, as I know, has a hydrophobic cavity. Therefore, it would absorb hydrophobic organic compounds. But the organic compound can also be removed with hot air since the interaction between the ...
2
votes
0answers
521 views

Boiling point and Intermolecular forces

After looking for proper reasons for boiling point orders, nobody could even explain why $\ce{CCl4}$ has a higher boiling point than $\ce{SiCl4}$, but after looking for patterns, in lots and cases of $...
2
votes
1answer
3k views

How to explain the periodic trends in boiling points in groups?

Observing the trend of boiling points of the compounds listed, choose the appropriate terms to fit into the blanks: \begin{array}{lr} \text{Compound}& \text{boiling point}\\\hline \ce{H2Te} &...
1
vote
0answers
38 views

Why London force dominates in Alkyl Halides

Why London Force is greater than dipole-dipole interactions in Alkyl Halides? As we know that most of the time London force is weaker than other forces. Then why in this case it's not so? ...
1
vote
0answers
29 views

Dipole moments of dibromoethene isomers

There was an exercise in my textbook asking to compare the dipole moments of 1,1-dibromoethene and 1,2-dibromoethene(Z). The answer in the textbook says that the dipole moment of 1,1-dibromoethene is ...
1
vote
0answers
191 views

Why does the dipole moment order of group 15 hydrides increase down the group?

The order given in my book is $$\ce{NH3} > \ce{SbH3} > \ce{AsH3} > \ce{PH3}$$ Phosphorous is more electronegative than arsenic and antimony. Then shouldn't the dipole moment be more in ...
1
vote
0answers
472 views

Dipole moment in aromatic compounds

Compare the dipole moment of the following: o-nitrophenol o-dichlorobenzene o-xylene What I thought was: o-dichlorobenzene should have the maximum, due to the acute angle and being more ...
1
vote
0answers
101 views

Closed shell structure & intrinsic molecular (electric) dipole moment

Does the closed shell structure of a molecule imply that it has an intrinsic (electric) molecular dipole moment? If so, why is that? I came across this in paper [1], which seems to suggest that this ...
1
vote
0answers
202 views

How is it possible to get an attractive charge-dipole interaction using the modified Coulomb law?

Vqµ = − qµ / (4π ε0εr r2) Say you had a negative charge, interacting with the positive end of a dipole then the charge would be -1.602 x 10-19 C and the dipole moment would always be a positive value....
1
vote
0answers
123 views

Is the momentary dipole in between a cell membrane due to the van-der-Waals forces?

There are van-der-Waals forces within non-polar molecules. I read it that is mainly due to the instantaneous movements of the electron cloud's distribution. When looking at symmetrical molecules like $...
0
votes
0answers
50 views

Theoretically predict the density of water

Is it possible to predict the density of water having just its molecular structure (basically obtain 1 g/cm3 at 3.96 °C)? Are you aware of research/textbook that dive into this topic? Is it able to ...
0
votes
0answers
163 views

Comparing dipole moments of Ortho,para and meta compounds

I was doing some questions based on dipole moment ortho,met and para compounds. I was not able to understand why dipole moment for \ce{C6H4NH2NO2} increases from ortho to para Because i think \ce{NH2} ...
0
votes
0answers
46 views

Finding Bond moment of O-H bonds of water

While finding bond moment of water we take the dipole moment of water as the vector sum of two O-H bonds and we calculate it to be 1.51D. But the lone pair is also present which affects the dipole ...
0
votes
0answers
160 views

Why don't I get the same value of percentage ionic character of a particular molecule from different equations?

About the ionic character of a polar covalent compound Pauling gave two equations as [1-$e^{.25(x_a - x_b)}] $% [18$(x_a-x_b)^{1.4}$]% Hanary and Smith gave the equation [$16(x_a-x_b)+3.5(x_a-...
0
votes
0answers
535 views

Deciding if a molecule is polar and non-polar in cyclic carbon compounds

While discussing about dipole moment of the compounds, our chemistry teacher told that the dipole moment will be 0 for 1,4-Dichlorobenzen, and for those compounds where same atoms or group of atoms ...
0
votes
0answers
106 views

Why is the molecular dipole the main determinant of whether a substance dissolves in another substance?

Consider a covalent molecule such as carbon tetrafluoride. In $\ce{CF4}$, each $\ce{C-F}$ bond is polar covalent. However, this substance is considered overall non-polar because each bond dipole ...