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.

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2k views

Trend in the boiling point of the hydrogen halides

The boiling points of the hydrogen halides are as follows: $$\begin{array}{cc} \hline \text{Species} & \text{Boiling point / }\mathrm{^\circ C} \\ \hline \ce{HCl} & -85.1 \\ \ce{HBr} & -...
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0answers
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Non-zero dipole moment of parahydroxy phenol [duplicate]

How can we explain the non-zero dipole moment of parahydroxy phenol? I know that it cannot be explained by inductive effect, and has something to do with resonance, but still how can we say it is non-...
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1answer
11k views

Why is phenol more polar than alcohol?

Why is phenol more polar than alcohol. I mean the benzene ring seems to be extremely unpolar. Furthermore, is the hydrogen bonding stronger in phenol than in alcohol? Are polarity and hydrogen bonding ...
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3answers
8k views

Dipole moments of pyrrole and furan

Why do pyrrole and furan have dipoles oriented in different directions?
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1answer
443 views

Using covalent or ionic radius when calculating dipole moment

When the ionic character of a bond is above 50% should I use ionic radius instead of covalent one when calculating the dipole moment? The formula I have for dipole moment is $\mu = \text{(% ionic ...
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2answers
65k views

Why don't polar and non-polar compounds dissolve each other?

Dipoles can also be induced in polar and non polar compounds, then why don't they dissolve?
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2answers
11k views

Why is CO practically nonpolar?

This question was in my book. According to me CO should be polar as it should have a dipole moment. But I found that the $\sigma$-electron drift from C to O is almost nullified by the $\pi$-electron ...
22
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2answers
10k views

Is Hydrogen Bonding a Type of Dipole Dipole Interaction?

I understand that dipole dipole forces is due to the attraction of the different partials charges of atoms in different molecules due to their different electro-negativities. For hydrogen bonding, ...
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3answers
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Is Hexafluorocyclohexane the “Most Polar” Small Molecule?

Earlier this year, there was a lot of attention when all-cis 1,2,3,4,5,6-hexafluorocyclohexane was synthesized*: Notably, C&E News quoted the lead author: This compound is remarkable for being ...
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1answer
5k views

Relationship between dipole moment of a molecule and electronegativities of constituent atoms

I want to know if I can calculate the dipole moment of a molecule given the electronegativity values for the atoms comprising it. I think that dipole moments determine the polarity of molecules, so ...
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3answers
638 views

At what frequency does a non-polar molecule acquire a dipole able to participate in London Dispersion forces?

London Dispersion forces are forces between non-polar non-ionic molecules that the random fluctuation of their electrons makes them temporarily dipoles. What is the frequency that this occurs? Every ...
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1answer
728 views

What are the structures of potassium superoxide and xenon hexafluoride? [closed]

I have 2 questions in mind: 1) What is the structure of the superoxides? More specifically, what is the structure of $\ce{KO_2}$? 2) What is the structure of and dipole moment for $\ce{XeF_6}$?
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Relationship between electric dipole moment and polarization?

$$\vec{p}_\text{ind} = \alpha \vec{E}$$ The induced dipole moment is the polarizability times the electric field vector. $$\vec{P}(\omega) \propto \chi^{(1)}(\omega) \vec{E}(\omega)$$ ...
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Confusion about direction of dipole arrow in alpha-helices and other molecules

I understand that molecular dipoles are electric dipoles. And electric dipole moment vectors point from the negative to the positive charge. In class we learned to draw these special molecular dipole ...
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1answer
243 views

Why do we say “approximation” in the dipole approximation in spectroscopy?

In the dipole approximation, the following relation holds: $$ \hat{V} = -\hat{\mu} \cdot \vec{E}. $$ When we say "approximation", I guess we want to point out that we are dealing with linear ...
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1answer
449 views

Bending of water and methanol towards a charged objects

I just had a question about why does water, methanol or any other polar substances tend to bend towards the charged object. I think it is because of a slight dipole dipole movement between the ...
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1answer
7k views

Is an ionic bond more like a covalent bond or an intermolecular force?

I have asked a question loosely asking this, where I confused terms and did not specify what I wanted to know here, so I formed a new question. What are the differences and similarities between ionic ...
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4answers
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Why is tetrafluoromethane non-polar and fluoroform polar?

Consider the Lewis dot structures of the molecules fluoroform, $\ce{CHF3}$, and tetrafluoromethane, $\ce{CF4}$:   My first line of thought is that both of these molecules are symmetrical (the ...
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Why is HCl not considered to have hydrogen bonding?

A molecule that has hydrogen bonding usually follows these two premises. 1.) There is a hydrogen atom involved 2.) Hydrogen must be bonded to a highly electronegative element which are ...
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2answers
107 views

Why is there a greater degree of separation in a dipole-dipole interaction?

My textbook says this: Electrostatic forces between two ions decrease by the factor $\frac{1}{d^2}$ as their separation distance, $d$, increases. Dipole–dipole forces, however, vary as $\frac{1}{d^...
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3answers
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How to calculate molecular dipole moment from a known wavefunction?

Say I have a molecular wavefunction as a set of molecular orbitals and want to calculate the molecule's dipole moment, but don't know how! I searched a lot but couldn't find any practical example. $$\...
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1answer
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How to explain the dipole moment anomaly of methyl fluoride and methyl chloride with respect to their hydracids?

I was checking dipole moment orders, and came across a very peculiar result: Methyl fluoride $(\ce{CH3F})$ has lesser dipole moment than methyl chloride ($\ce{CH3Cl}$), but hydrofluoric acid ($\ce{HF}$...
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Which intermolecular interaction is dependent on the inverse cube of distance?

The intermolecular interaction that is dependent on the inverse cube of distance between molecules is: hydrogen bond ion-ion interaction ion-dipole interaction London force Inverse ...
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0answers
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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 $...
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2answers
14k views

Why is fat nonpolar?

Why is fat nonpolar while water is polar? In water there is the $\ce{H-O}$ bond and the $\ce{O}$ is more negative, we have $\text{dipole = charge}* \text{distance}$ A fat molecule is like $\ce{H-O-C-...
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Polarity of the nitrate ion

We observe that nitrate ion has a trigonal planar geometry according to its lewis structure and the VSEPR theory. Its resonance hybrid consists of three contributing structure -three probable double ...
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1answer
886 views

Why the magnitude of dipole moment influences on FTIR % transmittance?

In 3:50 of this video two FTIR spectras are shown. He explains that the % transmittance (double bond in his example) depends on the dipole moment, $\mu = \delta \cdot d$. I understand that the ...
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1answer
6k views

Why does Phosphorus trifluoride molecule have dipole moment?

My book says that from drawing the Lewis structure for the molecule below, you can conclude that it has dipole moment. Can someone please explain why? I understand that the dipole moment expresses ...
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2answers
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What is the dipole moment direction of an aliphatic amine, i.e., R-NH2?

Since the electron donating property of $\ce{N}$ and $\ce{C}$ is different, there is partial charge transfer between $\ce{N}$ and $\ce{C}$ atoms in aliphatic amines, namely $\ce{R-NH2}$. What is the ...
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1answer
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Effect of inductive effect on boiling point,melting point and dipole movement

In my book the following was written:- Inductive effect is a permanent effect operating in the ground state of the organic molecules and hence is responsible for higher melting point, boiling point ...
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2answers
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How are reactivity and dipole moment related?

Recently, I came across a question: which of the two compounds has a greater reactivity; $\ce{NH_{3}}$ or $\ce{NF_{3}}$? It is known that despite the same structure the dipole moment of $\ce{NH_{3}}$...
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1answer
128 views

Why is hydrogen bonding more significant than any other interaction between dipoles?

Solvents can be categorized as polar and protic. I understand that to be protic there had to be a significantly polar bond involving a hydrogen atom. However, how is the a hydrogen bond different in ...
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1answer
732 views

What is the dipole moment of the most stable conformer of 1,1,2,2-tetrafluoroethane?

I want to know about the dipole moment of this molecule. I think the molecule has no dipole moment, but a book says me that it has a dipole moment.
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Why is the dipole moment of ethyl chloride larger than that of vinyl chloride?

The dipole moment of ethyl chloride is 2.10 D (J. Mol. Struct. 1990, 216, 9–26), and that of vinyl chloride is 1.42 D (J. Chem. Phys. 1960, 32 (1), 205–209). Why is this the case? I would have ...
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2answers
5k views

Non-zero dipole moment of hydroquinone

Why does hydroquinone possess a non-zero dipole moment? The $\ce{OH}$ groups present at para positions on the benzene ring should cancel the effect of each other... if there is a plane change then ...
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2answers
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Is carbon dioxide IR inactive?

I am told that carbon dioxide is IR inactive. This somehow strikes me as untrue or at best oversimplified, because yes, it is overall symmetrical, but can't $\ce{CO2}$ be induced to show asymmetric ...
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1answer
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Why is NaCl insoluble in CCl4?

Now I know it's something related to the fact that $\ce{CCl4}$ does not have a net dipole moment but I can't connect the dots.
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1answer
536 views

Dipoles and determining molecular (a)symmetry [closed]

What is a dipole? Also, how do you know if a molecule is symmetrical or asymmetrical? For example, are the following symmetrical or asymmetrical? Can you tell just from the molecular formula? Which ...
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2answers
5k views

Dipole moment of cis-2-butene

I need someone to back me up on this before I go confront my teacher: I was doing some analysis of the dipole moment of cis-2-butene. Let's say that the alkyl groups are both on top. Would the dipole ...
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2answers
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What is the bond angle of water?

I have been trying to find out the bond angle of $\ce{H2O}$, but every site I visit has a different answer. So far, I have found the following angles listed: Site 1: 104.4º Site 2: 107.5º OR 104.5º, ...
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1answer
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Dipole moment - calculation of percentage ionic character

Question: The dipole moment of $\ce{HBr}$ is $2.60 \times 10^{-30}$ and the interatomic spacing is $1.41$. What is the percentage ionic character of $\ce{HBr}$? What I know is that the percentage ...
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1answer
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Why does the lone pair of phosphine not contribute to its dipole moment?

Unlike ammonia, the lone pair of phosphorous does not add to the dipole moment of phosphine. My textbook says this is due to the presence of lone pair of phosphorous in $\ce{PH3}$ in an s-orbital. I ...
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2answers
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How does a lone pair of a central atom affect the dipole moment?

Dipole moment is the degree of polarity, i.e. the seperation of positive and negative charges. But I am not getting the intuition why and how lone pairs affect the polarity and dipole moment. I cannot ...
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2answers
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Does the distance increase as the polarity increases?

According to the dipole moment's definition, as polarity increases the distance between the centres of positive charge & negative charge increases.In the ionic bond ,as the polarity is maximum, ...
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2answers
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Dipole moment of symmetrical molecules

While studying dipole moment in organic chemistry, I got stuck at a particular statement written in the book : Symmetrical molecules without lone pairs of electrons will have $\mu = 0.$ The main ...
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2answers
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Why is water a dipole?

Water ($\ce{H2O}$) is a dipole. The reason why is simply because it is not symmetrical, there are more electrons on the oxygen side than on the hydrogen side, and the electronegativity of oxygen. But ...
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1answer
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Order of dipole moments

What is the order of dipole moments for $\ce{SO3, SiO2, P2O5,}$ and $\ce{Cl2O7}$? This question is from a book and the answer given is $\ce{Cl2O7 < SO3 < P2O5 < SiO2}$. Can someone explain ...