Questions tagged [molecular-orbital-theory]
Use of molecular orbital (MO) theory allows for an understanding of the observed properties (shape, reactivity) of molecules. The tag should be applied to all questions related to MO theory, from questions about the qualitative use of the theory to questions about the underlying quantum mechanics and applications in computational chemistry.
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I need a good 3d drawing of ferropericlase
I'm not a scientist, I'm an artist and I need a good 3d drawing of ferropericlase, where can I find that?
Thank you!
Niki
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Why do bonds interact with other bonds and exhibit overlapping effect?
In carbocations, alkenes and carbon free radicals during hyperconjugation, overlapping of molecular orbitals take place. So how and why does this happen?
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Molecular orbital energies for CH4 using group theory
I was learning how to use symmetry in molecular orbitals, I started with $\ce{CH4}$ the point group is $T_d$ I get the reducible representation for methane the reduce it to be $T_2+A_1$, the I applied ...
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HOMO and LUMO energy levels diagrams
Good time of day. I want to draw the same beautiful pictures in my work as I will attach below taking from some articles. Are there any programms or scripts which can do this? I would be glad if ...
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Why does the two OH bonds in H2O have different bond disassociation enthalpies? How does the bond cleavage happen here?
I came across this question, and in the text it was written as 'change in the chemical environment'. I wasn't satisfied with this explanation, so I am looking for a more detailed answer on this matter ...
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VBT and MOT at the same time!
In the SNAr reaction, it is said that the electron withdrawing groups should be at the ortho or para position for the effective electron delocalization to take place, and we draw Kekule's structure to ...
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How do two orbitals need the same symmetry to bond? Do they need the same mulliken label?
I heard that in order for two atomic orbitals to form a bonding molecular orbital, they need:
Similar energy
Similar symmetry
and Possibility of overlap with the same sign
but, for example in methane, ...
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Mulliken Labels: How do I tell apart E, doubly degenerate, symmetry apart from T, triply degenerate, symmetry for a molecular orbital?
With A and B, it's pretty simple. If you rotate the molecule about its principle axis to where the orbitals line up, and the signs change, it's Mulliken label has a B. otherwise, it's A.
I heard E ...
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In a few species such as dicarbon (shown below) why are the pi bonding orbitals of lower energy than the sigma bonding orbitals?
Normally the pi bonding orbitals are of higher energy because pi orbitals experience less direct overlap than sigma orbitals however in a few species this is not the case and I could not find any ...
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Why can s and p orbitals of one atom form hybrid orbitals but the overlaping of s & p orbitals of two different atoms don't form a molecular orbital?
So my question is in the title : Why can s and p orbitals of one atom form hybrid orbitals but the overlapping of one s orbital and one p orbital (perpendicular to the bond axis) of two different ...
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Why we apply Pauli Exclusion Principle to Molecular Orbital Theory?
Can we say that an electron with a specific set of quantum numbers of a fluorine atom is exactly the same as that of another electron with the same set of quantum numbers of another fluorine atom.
If ...
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Why is cyclohexane more polarizable than benzene?
Looking at figure 4.2 here, we can see experimentaly that cyclohexane is more polarizable than benzene.
Why is this the case?
Intuitively, I would think that because the orbitals in benzene are more ...
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Bond order of carbon monoxide and nitrosyl cation
The following question was asked in JEE Mains exam in 2022, a competitive exam for engineering in India.
The difference between bond order of CO and NO$^+$ is $\frac{x}{2}$ where $x$ = ____. (Round ...
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Which is better ligand, PH3 or PF3?
It confuses me that many researches pointed out different results about phosphine ligands properties (σ-donor and π-acceptor). Since both phosphine $\ce{PH3}$ and phosphorus trifluoride $\ce{PF3}$ ...
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What kind of hybridisation is there around the central carbon atoms?
I am currently working on an assignment and I am confused about what kind of hybridisation exists for the first condensed structure CH3CN. Does the CH3 have sp2 hybridisation? I suspect its that ...
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Why is there a point of orbits along with quantization in case of energy gaps?
As per my textbook and online sources. The definition of Energy bands I have found is this:
A) Energy levels:
( In a simplified view of an electronic structure of a single atom or isolated molecule.
...
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If a crystal has multiple oxidation states of the same transition metal element, is there only one possible configuration?
Here is the crystal structure of soluble Prussian Blue $\ce{KFe[Fe(CN)6]}$. The Fe(II) and F(III) are spaced alternatively like NaCl with cyanides in between. You can see that the places of Fe(II) and ...
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Table of molecular orbital extents — what does it even mean? [closed]
In molecular orbital theory, the term molecular orbital extents was mentioned, although I can't really picture it. Does molecular orbital extent refer to the spatial distribution of electrons in a ...
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How do the orbitals in atoms synchronize their phases during the formation of a bond?
Suppose I have two hydrogen atoms, each with one electron in their 1s orbital. Then we can represent the wave functions of these two as say $|\Psi\rangle_1$ and $|\Psi\rangle_2$ for each of the two ...
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Why does color of substances not disappear after some time?
Some compounds are colored due to HOMO-LUMO transition. We see the complimentary color to the frequency which the electron absorbs to get the high molecular orbital. But after some the electron should ...
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Why SCF-MO methods fail when treating bond-breaking processes?
I'm currently studying the EVB(Empirical Valence Bond) approach. While reading on this article (https://pubs.acs.org/doi/10.1021/ja00224a011), the author mentioned about the usage of SCF-MO formalism ...
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Help with drawing an Molecular Orbital (MO) diagram for organometallic complex
I do not understand how to draw the MO diagram for this question, i appreciate any help you can give on my 3rd yr Chem.
Have i understood this correctly?
QUESTION: Using an MO bonding picture and ...
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Do molecular orbitals in metals form bands like in wave interference? [closed]
For bond that's formed between two identical atoms, I naively understand that one molecular orbital is a bonding orbital and the other is an antibonding one, and I believe they have to do with the ...
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What is the molecular orbital diagram of hydroxide anion? [closed]
Context
I am a teacher, and, during a class, my student asked me to draw the molecular orbital (MO) diagram of the hydroxide anion ($\ce{HO-}$). First, I made the diagram on the left, and then, when ...
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Does I2 form coordinate covalent bond with PI3 in PI3.I2 (PI5)
As PI5 is uncertainly stated as the combination of PI3 and I2. There are suggestions that phosphorus donates its 3s electron pair to molecular orbital of I2 or I2 donates its electron to 3d orbital of ...
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How does MO theory explain the effect of directing groups on aromatic compounds?
From what I could find, this is usually explained using resonance. For example,
from Wade's Organic chemistry, 9th edition, p. 823.
but I can't figure out how to see this through the MOs of the ...
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If atomic orbitals are orthogonal, how can one mix then in Molecular Orbital Theory?
If two molecular orbitals are orthogonal, their net overlap is 0. Which means that the mixture of them would result in no observable change in any of the orbitals if they occur. However, this ...
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Are the density of states of bonding and the corresponding antibonding states complementary?
As for the bonding and the corresponding antibonding molecular orbitals formed between two types of atomic orbitals, are their density of states (DOS) complementary? This means if the DOS of the ...
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What is the driving force of Bartoli indole synthesis?
The Bartoli indole synthesis mechanism begins with a series of attacks on the nitroarene regent by the Grignard reagents. But the atom $\ce{O}$ in $\ce{-NO2}$ should be negative, and Grignard reagent ...
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Why is anhydrous trans-Bis(glycinato)copper(II) more stable than it's cis isomer?
As is shown in Ref.1, the trans isomer is much more stable, at least at molecular level.
Based on the crystal structural data from Ref.2 and atomic radii of O and N from wikipedia and some little ...
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Formal explanation for why ammonia prefers C3v over D3h
The 2 major possible geometries of ammonia are D3h and C3v, but it prefers C3v. My thought process is that this is simply Walsh's rule - the HOMO in C3v is bonding (2A1), whereas the HOMO in C3v is ...
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What can visual observations of pi-bonding MOs explain about LCAO expansion coefficients?
For examples of CO and N2, what can their MOs tell us about their expansion coefficients?
I've thought that in N2, its symmetric so the expansion coefficients would be equal from the pi-bonding MO due ...
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Molecular orbital picture in conjugated molecules - double bonds
I am a not a chemistry student but a physics student. Nevertheless, I am quite familiar with molecular orbital theory and similar quantum chemistry concepts. However, I have problems understanding the ...
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According to molecular orbital theory, is the antibonding orbital empy when electrons are found in the bonding orbital?
According to molecular theory when 2 atomic orbitals combine, 2 molecular orbitals will be created. So if the electrons are in the bonding orbital will the antibonding orbital exist and just be empy? ...
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If the 2 electrons of a hydrogen molecule are more likely to be found between the 2 hydrogen atoms, why does this diagram says otherwise?
So I am reading about bonding and antibonding molecular orbitals and i can't understand how does the probability diagram show that the electron density in the sigma 1s molecular orbital is greatest ...
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Energy of a molecule using MOs diagram (case of CH4)
I'm trying to find the ground state energy of CH4 in order to compare it with simulations I made. I came across this diagram of energy (not sure it gives the true energies though, if you could confirm....
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Is there a difference between Hartree-Fock method and LCAO?
I have to dive in some quantum chemistry for a quantum machine learning project and I came across the so-called Hartree-Fock method.
In one of the reference I used, they considered electrons as ...
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What are the highest and lowest (un)occupied molecular orbitals in this nucleophilic reaction?
I need to find the highest occupied molecular orbital and lowest unoccupied molecular orbital for this reaction. I'm not really sure where to start. I think it might be an SN2 reaction but I don't ...
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Role of spin of electron in splitting of orbitals
What will happen if there are electrons with opposite spins present in the orbitals of ligand and metal atom during the splitting of orbitals in crystal field splitting?
Magnetic fields of two ...
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Lewis structure of XeF2 that comes closer to reality?
Meanwhile, the hypervalency of Xe in XeF2 is explained by the 3c4e bond, where the p orbitals of the 3 atoms overlap to form a delocalized system of 3 MO's in which 4 electrons (two from the Xe p ...
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Molecular Orbital Diagram of NO
When we draw the molecular orbital diagram for molecules
For those that have less than or equal to 14 electrons we use the order "σ1s σ∗1s σ2s σ∗2s π2px,π2py σ2pz π∗2px,π∗2py σ∗2pz"
and for ...
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Would a hypothetical Og2 +235 form a chemical bond?
In a hypothetical (?) Og2+235 we would have a simple sigma bonding orbital occupied by one electron (leading to a bond order of 1/2). But how to take into account the giant repulsion of the two nuclei?...
user128572
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Why is the imine (C=N) bond so weak?
Nitrogen is similar to carbon in terms of electronegativity and size. MO theory suggests that the more electronegative N would result in a lowering of the of the π-bonding energy, E(πCN), below the E(...
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Reproducing Hydrogen Molecule Hamiltonian in OpenFermion
I am learning quantum chemistry at the moment and I'm trying to understand the Hamiltonian generated by the OpenFermion package. I'm now stuck at understanding how openfermion calculates the ...
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Self Consistent Field method and LCAO
I am reading about the Self Consistent Field Method and Linear Combination of Atomic Orbitals.
Suppose we have one electron and one nucleus, then we can solve the Schrodinger equation explicitly.
If ...
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Variation in the energy of the $\ce{\sigma_{2pz}}$ orbital
Is there a specific reason why the energy of the $\ce{\sigma_{2pz}}$ orbital varies relative to the $\ce{\pi_{2px}}$ and $\ce{\pi_{2py}}$ orbitals, depending on the atomic number of the atom?
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How to determine the characters of px atomic orbital in C4v point group?
How to determine the characters of px atomic orbital in $\text{C}_{\text{4v}}$ point group? I understand (px,py) is a set of basis function of E, and px and py are mixed by $\text{C}_4$ and $\sigma_{\...
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LCAO-MO ansatz for arbitrary hydrogenic molecule term
I am struggling to understand the connection between molecular electronic term symbols and translating the symmetries to the underlying wavefunction.
In particular, my understanding of the LCAO-MO ...
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On the energies of molecular orbitals
I found a useful (though simplified) scheme illustrating the energies of atomic orbitals, in crescent order:
I wonder if there was an analogous (simplified) scheme or rule for molecular orbitals, at ...
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sp mixing in $N_2$ vs sp mixing in CO
We were first taught that in B, C and N the bonding $\sigma_{2s}$ orbital repels with the bonding $\sigma_{2p}$ orbital which cause the energy level of $\sigma_{2p}$ orbital to increase. This increase ...
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