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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Why is the conjugate base of HCl (aq) a strong acid, very weak? Why when HCl(aq) dissociates the reaction only goes forward?
Mainly, I'm wondering why does HCl(aq) want to dissociate so much that when in ionic form, it is hard to recombine. Wouldn't it want to remain HCl to fill the octets? Thanks :)
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1answer
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Why does methane have 4-different bond dissociation energies?
I will elaborate on my question here.
In my Lecture Notes it is mentioned that for methane, there are 4 different $\text{C-H}$ bond energies. I plotted a quick graph of the bond energies to analyse ...
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Do hydrides, like NaH or CsH, also form H-bond?
I know that when hydrogen acts as a cation, it can form H-bonds with the electronegative ions or groups. But, is this also true for anionic hydrogens? Will they form similar bonds, other than the ...
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Why while writing resonating structures of CH2=CH-CH=CH2, the middle structure(as photo) is not considered or not counted as resonating structure?
Why the middle structure is not considered as resonating structure (or is it considered?) No rule is broken here, still I haven't seen the middle structure?
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1answer
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How electronegativity value is assigned to atoms like Na, Mg, Al etc [closed]
We know what electronegativity is the ability to attract shared pair of electrons in a covalent bond.
So that is why we don't assign electronegativity values of noble gases since they don't form ...
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Why does dilithium have a longer bond length than dihydrogen?
I've tried MO theory however they both have a bond order of 1. Which means we can not relate the bond order to the bond length.
My thinking -
I think that the h2 bond length is shorter due to only ...
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1answer
51 views
Do lone pair electrons go to the other side of the atom they are bonded to? [closed]
Usually lone pair electrons are put to one side of an atom in electron geometry of a molecule, but do they go to another side? Or are they localized in one side of the atom they are bonded to?
Thanks.
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Comparing bond lengths in metal carbonyls
Question:
It's solution is given as:
Now I don't understand which d$\pi$ electrons have been considered here. For example, in $\ce{Fe(CO)_5}$, according to this, number of d$\pi$ electrons would be ...
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Why can't hybridized orbitals form pi bonds(VBT)? [closed]
My friend asked me this question and even though I have an average knowledge, I couldn't answer him. Can someone help me?
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Lattice Energy and Stability in s block compounds
Lattice energy decreases down the group but stability of the compound still increases why?
For the purpose of this post I'll take alkali earth metal carbonate as an example.
As we go down the group ...
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Why does π-backbonding in a metal-carbonyl complex lead to a decrease in C-O bond strength?
I understand that π-backbonding in this complex involves the σ-donation of carbonyl to an empty d orbital of the metal, and the π-donation of the d electrons of the metal to the π* MO of the carbonyl. ...
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How does the force constant change when a heavier atom is used in vibrational spectroscopy?
(iii) The fundamental band in the IR spectrum of $\ce{^1H^{127}I}$ is found at $\pu{2308 cm^-1}.$ Calculate the force constant for the bond. Assume the molecule can be treated as a harmonic oscillator....
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What are the values of equatorial - equatorial bond angles of molecules like BrF5 or IF5?
I was looking for equatorial - equatorial bond angles in iodine pentafluoride but every Xrd and rotational I saw only mentioned axial-equatorial values. Is there is a reason why no one mentions ...
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1answer
50 views
What difference between pi bond and bent bond? Is it possible to replace sigma-pi bond model and use only bent bond instead?
Between sigma-pi bond and 2 bent bonds, is it actually equiavalence? Or there is specific molecule that require to be bent bonds and cannot exist as pi bond and vice versa? I felt like we actually don'...
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Why is HF much more covalent than KI despite having a greater electronegativity difference? [duplicate]
Generally, the percent of ionic character in a two-element compound correlates quite well with the difference in the electronegativities of the two elements making up the compound, as can be seen in ...
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1answer
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Why are steric effects repulsive?
Normally, I think about orbitals interacting in the context of bonding. When two atomic orbitals overlap, they can do so in-phase or out-of-phase. The in-phase overlap results in a bonding molecular ...
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2answers
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Confusion regarding $\delta$ charge compared with electronegativity
I heard on a lecture of an online site that, let us say, we have two orbitals (1 and 2). Now, it will be like a spherical cloud. Now, what they say is that
Now, we can notice that for orbital number ...
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How can I Solidify / cure silicon caulk used to create tubing
Curing and preventing silicon caulk from sticking to itself
Food Grade RTV Silicone Sealant Adhesive Clear 10.3oz when creating tubes.
Some videos show using hot water and some videos show using cold ...
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1answer
68 views
Comparing O−O bond length in hydrogen peroxide and dioxide(2−) ion
Problem
How can we qualitatively compare the bond lengths between $\ce{H2O2}$ and $\ce{O2^2-}?$
Answer
Attempt
I tried using molecular orbital theory, but since both have peroxide $\ce{O2^2-},$ the ...
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2answers
126 views
What is the definition of thermodynamic stability?
The term thermodynamic stability is used on this site, but I can't find a good definition. Is is a quantitative or a qualitative concept? Does it apply to a single compound, or a pair of compounds? ...
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In dative bond S→ S, why are the Oxidation state of donor S = +2 and recipient S= -2 although both of them have the same electronegativity?
We know that if the dative bond is directed towards less electronegative element, it is ignored while calculating the oxidations state and it is considered as +2 for donor and -2 for the recipient ...
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1answer
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Estimating BDE Values
I'm having trouble understanding how to "estimate" the value of the BDE for the compound shown below (I believe it is a secondary benzylic C-Br value) shown below (the 58 kcal/mol). We are ...
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what does “overlapping” of orbitals mean and why does it effect bond strength(VBT)?
according to valence bond theory, bonds are formed due to the pairing of unpaired valence electrons due to the overlap of half-filled orbitals, and the strength of the bond depends on the extent of ...
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Can the energy used required to break a molecular bond of plastic (e.g. - PVC) be used to dissociate plastics into its constituent elements?
Dear Molecular Chemists and Physicists,
Pardon my ignorance, but why can not plastic polymers be broken down into their constituent elements?
Common bond energies are shown in these two separate ...
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If bonds are not physical things, what is meant by bond rotation? [closed]
I’m not sure if this is a stupid question or not, but since bonds are not physically there as such, what does it mean when it can rotate? And how do pi bonds prevent rotation if they are not physical?
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1answer
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Are polar bond stronger than non-polar bonds?
I came across Pauling's electronegativity scale in which he noticed that the experimental bond enthalpy of X-Y is always greater than the average of X-X & Y-Y and proposed that the difference, D, ...
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1answer
88 views
Strength of the hydrophobic interaction
How strong is the "hydrophobic force"?
Hydrophobic interactions are weak interactions but can have greater strength than hydrogen bonds. I find the strength of the hydrogen bond in ...
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0answers
39 views
How are compounds like NO, NO2, and NO3 formed?
Why do Nitrogen and Oxygen make compounds other than N2O3? For example: NO, NO2, or NO3?
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The covalent bond in HCl and the Lewis model
Can the formation of the covalent bond in HCl be explained through the hybridization model?
We know for sure that it can be explained by the theory of molecular orbitals. In this way, it would be ...
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93 views
What is the relationship between polarisation of ion and their bond strength/enthalpy?
Starting with things I Know:
Size and charge of ions affect the bond strength and the lattice energy of ionic compounds
Decrease in ionic radius(size) increases the bond strength and increases the ...
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Why doesn’t AlCl3 form the dative bond within the same molecule? [duplicate]
AlCl3 is said to be an electron deficient molecule as Al only has 6 electrons in its valence shell. Why doesn’t it just form a dative bond with one of the chlorine’s? I know this gives the more ...
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Is this bond Ionic or Covalent, and why? AlBr [closed]
We know a compound could form between NaCl because they are +1 and -1 ions which make them both into a complete valence set.
Could a compound form between Al and Br, for example, and what type of bond ...
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2answers
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How is 4H‐1,4‐oxazocine aromatic?
I’ve found 4H‐1,4‐oxazocine in my chemistry book and I’m perplex as it states as aromatic:
I can count 6 electrons on p orbitals which could satisfy Hückel’s $n = 1,$ but the oxygen is sp3-hybridized....
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1answer
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Regarding the probability density of finding an electron in between a bond
I'd found the image attached on a website explaining the molecular orbital theory.
My question is, shouldn't the graph have a maximum at the middle of the two hydrogen atoms? since my intuition tells ...
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Why does tungsten(VI) oxide have higher melting point than tungsten(VI) fluoride?
I'm learning about ionic bonding and polarizability. Larger anions with higher charge should make more polarized ionic bonds. $\ce{O^2-}$ is both larger and has higher charge than $\ce{F^-}.$
So, why ...
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Why are there only a few types of sigma overlaps?
While studying σ-bonds, I saw that only s–s, s–p and p–p orbital overlaps are being taught. But are there more such cases possible? Because apart from s and p, there are also d and f orbitals.
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Silicon–Boron Covalent Bond
This is a semiconductor-related question, but in order to understand the acceptor level energy state of boron in bilicon, I figured I'd ask here for hints.
Boron is a p-type material when introduced ...
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1answer
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How can I know which molecule is more stable when bond order it's equal?
So, I was wondering, I have these molecules $\ce{O^+2}$, $\ce{O^-2}$, $\ce{O2}$ and $\ce{C^+2}$.
When I try to find their bond order and their magnetic nature I get this:
$\ce{O^+2} = \frac{1}{2} \...
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1answer
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Why do phosphorus and sulfur have variable valences?
I have learnt that phosphorus and sulfur have valences 3, 5 and 2, 4, 6 respectively because of vacant d orbitals. But how?
Phosphorus' configuration is $\mathrm{[Ne]3s^23p^3}$. There are 3 unpaired ...
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2answers
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Half sigma bonds
$\ce{N2+}$ has $2$ $\pi$-bonds and a half sigma bond.
First of all, how can a "half" sigma bond exist? Usually when we encounter non integral bond orders, it is mostly because of resonance ...
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1answer
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Does boron form compounds without covalent bonds?
I have read that boron, due to the very high sum of its first three ionization energies, it is not able to form its +3 ions, and thus it generally forms only covalent compounds. But in a popular ...
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1answer
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Why No Change in Polarizability in Asymmetric Stretch?
In order for a molecule to be Raman active, there must be a change in the polarizability, meaning that there must be change in the size, shape or orientation of the electron cloud that surrounds the ...
3
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1answer
108 views
Why does the C−H bond dissociation energy vary in a homologous series of primary alcohols?
Specifically, for the primary carbon atom in the alcohol. Here is bond dissociation energy (BDE) data from chapter three of Luo's Comprehensive handbook of chemical bond energies [1] (boldface refers ...
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Is this diagram correct for difference between 2N and N2
There is 1 $\ce{N2}$ molecule formed with 2 atoms of nitrogen.
2N is 2 separate nitrogen atoms which have not formed any bond.Reasons could be that they didn’t get enough energy to form bond so they ...
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1answer
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Why do amides require much harsher conditions for hydrolysis than esters?
Amides require much harsher conditions to hydrolyse than its ester homologue. An explanation given is that the orbitals holding the lone pair on the nitrogen overlaps with the C=O π-bond to give ...
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Why is the carbon fluorine bond stronger than the carbon oxygen bond?
From this wiredchemist.com, I obtained values of the bond dissociation energies of the $\ce{C-O}$ and $\ce{C-F}$ bonds:
\begin{align}
D_0(\ce{C-F}) &= \pu{485 KJ mol-1}\\
D_0(\ce{C-O}) &= \...
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Why does B12H12 Borane not exist? [duplicate]
Whenever I searched "$\ce{B12H12}$ Borane", I can't seem to find anything, and get met with only the dianion of $\ce{B12H12}$. Why doesn't $\ce{B12H12}$ exist on its own?
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How to break bonds of tea on a curtain? [closed]
If I throw tea on my curtain , it looks as if the curtain has absorbed tea molecules but is it true to say that since matter has spaces between them.So these tea molecules go into that space and stick ...
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Help determining normalisation constant in SALC of methane
We have been told that a symmetry adapted combination of four hydrogen orbitals is used to create localised hydrogen orbitals for methane. These orthonormal combinations are denoted ψa1, ψt’2, ψt’’2 ...
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Why does matter have spaces between them? [closed]
If you mix sugar Crystal in a glass of water and mix it well, the level of water will not rise.The reason they say is that matter have spaces between them.If matter have spaces between them , How ...
