All Questions
Tagged with molecular-orbital-theory electronic-configuration
31 questions
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H_2 Hamiltonian matrix off diagonal elements between RHF state and open shell
I am currently trying to calculate the Hamiltonian matrix of the H$_2$ molecule. To describe that I use the second quantized molecular Hamiltonian:
$\hat{H} = \sum_\sigma\sum_{pq} h_{pq} a_{p\sigma}^\...
3
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1
answer
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Why are Mo(NR2)3 complexes isolobal with the nitrogen atom in N2
In a Molybdenum complex of the form Mo(NR2)3, the Mo is in the oxidation state of +3, leaving it with 3 d electrons. When combined with an additional 2*3 electrons from the ligands, this leaves it ...
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Jahn-Teller Distortion: How to compare magnitudes (in Cu2+ complexes)?
Octahedral complex of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper(II) complexes will who the maximum structural distortion? (en - ethylenediamine)
(A) $[Cu(...
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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 ...
- 284
1
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1
answer
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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 ...
- 119
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1k
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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 ...
- 342
2
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96
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Hartree Fock calculations on F2 don't match the traditionally taught MO diagram
I ran some Hartree-Fock calculations on F2 to visualize the MOs, and the energy levels don't match the trend commonly taught (shown here: https://chem.libretexts.org/Courses/...
- 21
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Do diatomic isoelectronic molecules have the same bond order even when the octet rule is not followed?
It can be observed and proven that diatomic isoelectronic molecules have the same bond order when they follow the octet rule (upto 3rd period elements). But what about when they do not follow the ...
- 83
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How do the spin-matrices change in systems without spherical symmetry?
The (non-relativistic) spin matrices of a free electron, with $z$ as the quantization axis, read:
$$
\boldsymbol{S}_{x}=\frac{\hbar}{2}\left[\begin{array}{ll}
0 & 1 \\
1 & 0
\end{array}\right],...
- 181
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Why SCF procedure in Hartree-Fock doesn't keep returning the same coefficients?
In the context of Hartree-Fock theory, using Roothaan formalism, we write:
FC=SCE
where F is the matrix of the Fock operator, C are the coefficients to be used in the construction of the wave function ...
-4
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1
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Do higher orbitals have more energy or less energy? [duplicate]
I've recently learned that as an orbital gets larger, its energy gets closer to 0. Before this, I learned that when an electron moves down an orbital it releases the energy difference between those ...
- 101
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1
answer
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Book Recommendation for Molecular Orbital Theory [duplicate]
I posting my question here since I have seen similar questions but I haven't found the specific answer I am searching for. I am seeking textbook recommendations on Molecular Orbital Theory with ...
- 167
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1
answer
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Electron pairing in atoms
A question asks:
This question refers to isolated gaseous atoms. In which atom are all electrons paired? Ba, Br, S or Si?
I thought it was Ba as its electron configuration is [Xe] 6s2.
However, ...
- 205
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370
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Why are sulfur trioxide and nitrate not isoelectronic, even though both have the same number of outer electrons?
Though $\ce{SO3}$ has the same number of outer electrons as $\ce{NO3-}$, the two are not isoelectronic.
This statement is from JD Lee, but I could not understand why is he calling these two molecules ...
- 1,246
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How to explain the excited states in the dinitrogen cation?
The $\ce{N2^+}$ molecule has the molecular orbitals
$$\ce{\sigma(1s)^2\; \sigma^*(1s)^2\; \sigma(2s)^2\; \sigma^*(2s)^2\; \pi(2p_x)^2 \; \pi(2p_y)^2 \; \sigma(2p_z)^1,}$$
which can be seen on the ...
- 1,267
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Why do halogens have odd numbers as oxidation number?
Halogens like $\ce{Cl}$ always exhibit $+7,+5,+3,+1,-1$ as their oxidation numbers. I found the following answer after checking several sources:
Halogen atoms have $7$ electrons in their valence ...
- 631
16
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1
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803
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Why is an energy cost associated with splitting the HOMO spins in singlet oxygen?
The molecular orbital schemes for both forms of singlet oxygen ($\mathrm{^1\Delta_g}$ and $\mathrm{^1\Sigma_g^+}$) and triplet oxygen ($\mathrm{^3\Sigma_g^-}$) are typically given as shown in the ...
- 68.7k
8
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1
answer
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The electron configuration and electron density distribution in singlet oxygen
The molecular orbital schemes for singlet ($\mathrm{^1\Delta_g}$) and triplet oxygen ($\mathrm{^3\Sigma_g^-}$) are typically given as shown in the image below.
Figure 1: Molecular orbital schemes of ...
- 68.7k
1
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258
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The affect of effective nuclear charge on energy gap between subshells
A few days ago my teacher taught me about $\mathrm{d}$ orbital contraction. He said that in $\ce{SF6}$ the hybridization of sulphur is $\mathrm{sp^3d^2}$. He said that although the $\mathrm{d}$ ...
- 179
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"NBO diagrams" versus MO diagrams
Molecular orbital diagrams are well known by chemists.
According to Wikipedia (emphasis mine),
A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical ...
- 2,883
2
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1
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Why is the iron(II) on the heme molecule depicted as having 6 electrons in its 5 d non- and anti-bonding orbitals?
Approximating the $\ce{Fe}$ complex as a square base pyramid ($D_\mathrm{4h}$ symmetry) with 5 $\ce{N}$ ligands, My electron count of the system gives me 16 electrons – 10 from the $2\times 5$ $\ce{N}$...
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1
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259
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Does the weird 4s and 3d rule apply for much of the p-block from Ga-Rn?
In the transition metals, $4s$ has a higher energy level than $3d$, because in ionization, the electrons from the $4s$ energy level are lost first.
I was thinking that this might be the same for much ...
- 614
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0
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1k
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Transition of electron from HOMO to LUMO?
Molecules usually have certain number of (doubly) occupied molecular orbitals and an infinite number of unoccupied molecular orbitals but the probability of electron makes the orbitals shapes so, how ...
6
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3
answers
5k
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What is the highest known bond order?
In science we learn about single, double, and sometimes triple bonds. From a quick search I have found up to sextuple bonds.
Is there a maximum bond order? If yes/no, what causes this?
- 121
27
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2
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137k
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Molecular orbital (MO) diagram for N2 and N2^-
I have been taught that the MO diagram is different for molecules with 14 or less electrons than the one used for molecules with 15 or more electrons.
For $\ce{N2}$ the orbitals in increasing energy ...
- 271
2
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1
answer
1k
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MO for $N_2^{2-}$
Could someone please show me the MO diagram for $\ce{N_2^{2-}}$? What I did was since N has 5 valence $\ce{e^{-}}$, then $\ce{N_2}$ must have 10, and $\ce{N_2^{2-}}$ must have 12. And $\ce{N}$ has $s$ ...
- 637
13
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3
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672
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What is the usage of orbitals more complex than f orbitals?
Every high school learner, in each corner of the world, faces the lesson History of Atom during his courses, just as I did. We learned about s, p, d and f orbitals, though there were no signs of ...
- 10.8k
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2
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Why is diboron (B2) paramagnetic?
Why is $\ce{B2}$ paramagnetic? It's just 2 borons with a triple bond between them. Aren't all the electrons paired?
- 309
3
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1
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449
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Why is the 8-electron rule more important than the 2- or 18-electron rule
Why is the fulfilled electronic configuration of only $p$ orbital is stable. I mean why $II-B $ group with fulfilled $d$ orbital,$II-A$ group with fulfilled $s$ orbital...are not stable. Why makes $p$...
- 237
3
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2
answers
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Where does the 9th electron go in a N=O bond?
In the first resonating structure you can see 5 unpaired electrons and 4 shared electrons on nitrogen, then isn't this a extended octet? If it is so, then in which orbital that 9th electron is ...
- 133
22
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1
answer
590
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Is the Springborg 6D phase space model used in modern molecular orbital modeling?
In various papers written in the 1980s, Michael Springborg explored an interpretation of the Wigner phase space function as an electron density in a six-dimensional $(q,p)$ phase space. He applied it ...
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