Questions tagged [bond]

For questions about chemical bonds (ionic/covalent/etc.), their properties (length, energy, angle, etc.) or their relation to other molecular properties (intermolecular forces/dipole moment/etc.). Do not confuse this tag with [lewis-structures], [dipole], [intermolecular-forces], etc.

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197 views

Bond length in cyclic organic compound

Why is bond length $(a)$ greater than that of $(b)$? Is this because $\ce{-NH}$ is electron donating group (+M) and this results in a higher electron density in the ring causing repulsion?
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2answers
380 views

What effect does lone pair have on bond angle? [closed]

I have read that the presence of lone pair decreases the bond angle.Shouldn't it increase the bond angle since there is repulsion between the electrons?
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Can two metals combine to form a compound? [closed]

what I mean is can a metal react with another metal to form a compound? non-metals react with each other and form compounds with covalent bonds can the same happen with metals.
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133 views

Bonds in R-H3N+ group

Source: Wikipedia I am confused about the ammonium group in this molecule. I can see that we have a nitrogen atom and 3 hydrogens. The group is attached to a carbon. Nitrogen has atomic number 7 so ...
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1answer
107 views

does stirring honey make it less viscous? [closed]

After making some research, I found that crystallized honey does get less viscous as we stir it, so is it the same thing with pure honey or not? and also if not could we use the Zahn cup experiment to ...
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1answer
55 views

Do SALC-AOs really belong to their symmetry species?

I'm working through a molecular symmetry textbook and something keeps nagging at me. If I derive the SALC-AOs for NH3 (using the projection operator method), I'll get A1: $ \frac{1}{\sqrt{3}}(\...
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0answers
73 views

Bond strength of carbon compounds

I read online that C=O is more stronger than C=N and the reason behind this was, 'Since bond between C and O is more polar hence it will have a slightly higher ionic nature than C and N. As we know ...
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1answer
53 views

Ionization and bond energy of isotope [closed]

Is there a database with the direct values, or the ingredients to calculate them, for ionization and bond energies of isotopes (i.e. $^{17}O_2$). If I understand it right, ionization energy can be ...
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476 views

Dipole moment difference between ch2f2 and ch3f [duplicate]

In CH3F and CH2F2 the net dipole moment increases from 1.82 to 1.97 while in all other halogen substituted carbon atoms the dipole moment decreases. In the case of CH3Cl and CH3F the chlorine ...
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0answers
65 views

What is the difference between a dπ-dπ and delta bond [closed]

I have always been wondering the difference between a dπ-dπ bond and a delta bond. What are the situations that either bond is formed in overlap of two d orbitals.
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Molecular Geometry of IF₄⁺

Recently I came across a question asking for the geometry of the aforementioned molecule. The answer key claimed the shape as an irregular tetrahedron, but as per my knowledge, it should have been ...
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443 views

Molecular orbital diagram for I₃⁺ cation

Do I need to go through the whole process of reducible representations/projection operator method to come up with the bent SALCs for the $\ce{[I3]+}$ molecule? Or is it simpler than that?
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Can bond rotation take place in Pinacol-Pinacolon rearrangement

I was given a question of pinacol pinacolon rearrangement of butan-2,3-diol where the methyl groups were anti to the respective hydroxy groups. Can the C2-C3 bond be rotated to allow hydrogen to be ...
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1answer
801 views

Why do stable compounds have a lower heat of combustion?

My brain somehow doesn't accept that more stable compounds require have less enthalpy. Isn't it like, if a compound is stable, it requires more energy to break the bonds because the compound doesn't ...
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1answer
95 views

How can I make AgNO3 more basic? [closed]

Is there anything that I can add to the AgNO3 solution that will make it more basic without forming a precipitate such as reacting with OH or HCl? Please be more specific and give an example.
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Is the total ionic-dipole bond (hydrogen bonds) acting on an ion stronger than the lattice energy holding the ions together?

When magnesium chloride dissolves in water, its $\Delta H^⦵_\mathrm{sol}$ is negative. Since $\Delta H^⦵_\mathrm{sol} = \Delta H^⦵_\mathrm{hyd} - \Delta H^⦵_\mathrm{latt},$ this means $-\Delta H^⦵_\...
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Does direction matter in breaking a bond?

Im not sure if this question belongs here or in another community. I was wondering if the direction that we apply a force in order to break a bond matters and how it affects strength. Say we have one ...
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40 views

Hybridization theory (orbitals used in different hybridizations)

Why is $d_{x²-y²}$ orbital used in $sp^3d$ (square pyramidal geometry) while $d_{z^2}$ orbital in $sp^3d$ (trigonal bipyramidal geometry)? I came across this information while reading J.D.Lee Concise ...
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120 views

For an electron arrangement diagram, is it necessary to show the inner electron shells or is it customary to only show the valency electrons?

Which electron arrangement diagram is correct? The one that shows all electron shells or the one that only shown the valence electron shell?
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1answer
468 views

Why are the acidities for H-CH3 and H-OH so different?

I was comparing the acidity of H-CH3 and H-OH, and a lot of things weren't making sense. Generally, the process of turning H-X into $H^{+}$ and $X^{-}$ can be broken into 2 hypothetical steps: 1.) ...
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32 views

Why is average bond enthalpy measured by homolytic fission?

Average bond enthalpy: the energy required for 1 mole of a specific gaseous bonds to undergo homolytic fission Why specifically homolytic fission? Is it to allow comparison, but if that were the case,...
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1answer
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Why is the carbon monoxide triple bond stronger than the nitrogen-nitrogen triple bond?

The $\ce{CO}$ triple bond has a bond enthalpy of 1072 kJ/mol while the $\ce{N2}$ triple bond has a bond enthalpy of 945 kJ/mol, at least according to my source. The molecules are isoelectronic, so I ...
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640 views

If all bond angles in AX₃ are the same, then which of the following are correct conclusions about AX₃?

Question If all bond angles in $\ce{AX3}$ are the same, then which of the following are correct conclusions about $\ce{AX3}?$ (A) $\ce{AX3}$ must be polar. (B) $\ce{AX3}$ must be planar. (C) $\ce{AX3}...
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52 views

Reason behind more Reactivity of Unsaturated Hydrocarbons [closed]

My textbook says that unsaturated hydrocarbons are more reactive than saturated ones. But double and triple bonds are stronger than single bonds. What is the explanation for this?
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93 views

Why do certain signals in proton NMR experience extensive splitting despite only having 1 neighbour?

I came across the compound 3-methylpentan-2-ol. Looking at its proton NMR spectra, it seems there is a lot of splitting for the signal at 4 ppm. I'm assuming that the 4 ppm represents the proton in ...
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1answer
111 views

Covalent Bonds and Ionic Bonds [duplicate]

Covalent bond is a strong bond compared to Ionic Bonds but Ionic Compounds have higher melting and boiling points then covalent compounds. Why?
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For bond dissociation energies (BDEs) of double and triple bonds, is number shown in tables for that second or third bond? Or all of them?

Simple, 'dumb' question.... Is the kJ/mol number given in tables of bond strengths or bond dissociation energies , when it comes to double and triple bonds, just for the 'last' bond or for both (or ...
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1answer
87 views

What are the products of these 3 reactants? Acetic Acid + K2CrO4(aq) + Ba(NO3)2(aq) [closed]

Acetic Acid + K2CrO4(aq) + Ba(NO3)2 (aq) —> ?
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1answer
179 views

For molecular orbitals, how is an energy of zero set or defined?

When labeling the energies of molecular orbitals, often some anti-bonding MOs are shown with a positive energy. For example, MolCalc has the following energies for methane (the anti-bonding MO #8 at +...
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0answers
51 views

Multiple bonds solely with sp3 hybridised orbitals? [duplicate]

I have fond that similar question has been asked already (why don't carbons use sp3 instead of sp2 orbitals to make double bonds?), but I don't think it was formulated in a manner that was ...
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3answers
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Do molecules with bridges through rings exist?

Do molecules with bridges through rings (in a manner illustrated by this) exist? I sometimes get results like this when doing Energy Minimization on molview.org. For example: Is this actually a ...
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1answer
123 views

Why do ionic compounds form in the exact ratios that they do instead of more variable ratios? [closed]

I read that e.g. $\ce{Mg^{2+}}$ and $\ce{Cl-}$ come together because of electrostatic force or coulomb force and form an ionic bond. Then why is the formula $\ce{MgCl2}$? Why does one $\ce{Mg^{2+}}$ ...
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1answer
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Why do boiling points of alkanes and alcohols become closer with increased chain length

I came across this graph, which clearly shows a large difference between the boiling points of alkanes and their equivalent alcohols. However, it is clear that as chain length increases, the ...
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Discussion about Warren-Cowely Parameter

The Warren-Cowely Parameter (WCP) for short range solution order is defined as: $$\mathrm{WCP}_{ij} = 1 - \frac{Z_{ij}}{x_j \cdot Z_i}$$ where $Z_{ij}$ is the partial Coordination Number (CN) of ...
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1answer
166 views

Only valence shell electrons participate in bonding then how is Cr in H2CrO4 forming 6 covalent bonds although it has only 1 valence electron?

The structure of $\ce{H2CrO4}$ is as follows: Shell configuration of chromium is 2,8,13,1 i.e. it has only 1 valence electron and only valence electron participate in bonding but Chromium in the ...
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3answers
2k views

Do metals form covalent bonds besides ionic and cordinate bond? [closed]

My chemistry textbook says that metals form ionic or cordinate bonds whereas non metals form covalent bonds. But in another textbook I read that Lithium, Beryllium, Aluminium, Chromium, Manganese etc, ...
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1answer
609 views

Why aren't all bonds in cyclobutadiene not equal? [duplicate]

Cyclobutadiene is like benzene in that it has alternating single and double bonds in a ring. However, it's bonds are not the same length, the double bonds being shorter than single bonds. The molecule ...
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0answers
68 views

Why sigma bond has C2 symmetry not C∞?

I have seen some books indicated sigma bond has C2 symmetry. I understand pi and delta bond change their signs about C2 and C4 rotation about bond axis, but I don't understand why sigma bond has C2 ...
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1answer
215 views

Heats of formation of neutral molecules and homolytic vs heterolytic bond dissociation in mass spectrometry

I am currently studying the textbook Mass Spectrometry, third edition, by Jürgen H. Gross. Chapter 2.4.3 Bond Dissociation Energies and Heats of Formation says the following: Great efforts have been ...
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Bonding in molten silicon dioxide

Solid silicon dioxide has a giant lattice structure with single covalent bonds, while in the gas phase it has a molecular carbon dioxide-like structure. But what about in the liquid phase? Would it ...
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0answers
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Why are stable ionic charges so strongly related to the group number?

Why do lighter elements have ionic charges so strongly related to the group number? For example, why does $\ce{Al}$ only show +3 ionic charge? The basic concept of stability in an ionic compound is ...
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Why do diplumbenes (Pb=Pb double bonded compounds) break apart in hydrocarbon solution?

In group 14, the double bond becomes increasingly weaker down the group. Our lecturer told us that many distannenes ($\ce{>Sn=Sn<}$) and almost all diplumbenes ($\ce{>Pb=Pb<}$) dissociate ...
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1answer
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Geometry of Ni(acac)2

The complex $\ce{Ni(acac)2}$ is paramagnetic as expected , i.e it has two unpaired electrons giving rise to a magnetic moment of $ \sqrt{8}$ BM but doesn't have the tetrahedral geometry consistent ...
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2answers
414 views

How energy is released when chemical bond is formed?

In books it is commonly written that whenever a chemical bond is formed the energy of the molecules/atoms gets lowered and hence energy is released. This is generally explained by diagrams like this ...
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In vivo, does it take energy to move double bonds from cis to trans long chain unsaturated fatty acids

In vitro, long chain fatty acids may yield more energy when bonds break, but in vivo, I understood that energy is burned before unsaturated fatty acids can be oxidized because the side groups with ...
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174 views

How much electron hybridization and bonding occurs in liquid helium?

Helium is the only element which does not freeze at atmospheric pressure, and only forms a liquid at around 4 Kelvin due to weak van der Waals forces. I'm interested in knowing roughly how much ...
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0answers
344 views

Comparison of I-F, Br-F, and Cl-F bond strengths

From Chemistry of the Elements by Greenwood and Earnshaw [1, p. 833]: Figure 17.9 Mean bond energies of halogen fluorides. This shows the mean bond energy for $\ce{X-F}$, where $\ce{X}$ is a ...
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2answers
93 views

What repulsion keeps non-hydrogen atoms at a distance: between inner shells or between nuclei?

Bonded or not, when two atoms or ions come closer than the bond distance or the van der Waals distance, the energy increases drastically. What is the underlying cause of that repulsion? The repulsion ...
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3answers
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Strength of Hydrogen Bond and Angle

This link has a short paragraph on the very first page, which says: "There are two useful criteria to evaluate the presence and the strength of a H-bond. The first is to look at the distance between ...
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1answer
86 views

How to check whether intramolecular hydrogen bonding takes place in cyclic compounds?

How can we confirm or have a clear idea whether hydrogen bonding is taking place in substituents of cyclic compounds? For example, it takes place in ortho-nitrophenol, but it doesn't take place in ...

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