Questions tagged [orbitals]

An orbital is a one-electron wavefunction, usually derived by solving the Schrodinger equation. This tag applies to questions about all forms of orbitals; additionally, questions about the construction and properties of molecular orbitals should be tagged with [molecular-orbital-theory].

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38 views

Existence of Hartree–Fock limit

I'm reading McQuarrie's Physical chemistry textbook [1]. On p. 281, the author explains: If we use a more flexible trial function of the form in which $\psi(\mathbf{r_1},\mathbf{r_2})$ is a product ...
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1answer
34 views

What is the derivation of the formula for finding number of pure and hybrid orbital?

I am studying Organic Chemistry. Recently I came up with the formula for finding number of Pure and Hybrid orbital that can be present in a organic compound , That is Number of Hybrid Orbital = ...
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Reaffirming the idea of orbitals in ionisation energy? [closed]

From my understanding the pattern that follows is thus: H -> He: Increases due to an increase in protons, without new shielding electrons He -> Li: Decreases due to a new shell (core electrons ...
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1answer
163 views

Which software to use to output molecular orbital diagrams? [closed]

I want to output a molecular orbital diagram. Can anyone recommend a software to do this? Also I searched for a python module, but didn't found a pure solution. Maybe I am using the wrong keywords. I ...
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45 views

Energy levels for single electron atom [duplicate]

Is it because for single electron atom, energies of all the orbitals with the same n are the same (degeneracy). For example, hydrogen atom energy levels, the electrons are degenerate and also, single ...
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1answer
36 views

Benzene - MO states [closed]

When constructing the different combined molecular orbital combinations (from the original 6pi orbitals) we normally say that p orbitals "combine" to produce the different molecular orbitals ...
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1answer
81 views

Orbital overlap and bond strength

In Peter Sykes' A Guidebook to Mechanism in Organic Chemistry, it says that sp3 orbitals have greater relative overlap compared to sp bonds. We know that the $\ce{C-H}$ bond is shorter in ethyne ...
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61 views

What are the rules for constructing Kohn-Sham orbitals?

I just recently began to study quantum chemistry and need some clarification for the construction of Kohn-Sham orbitals. Consider a system of several atoms. Let there be $N$ electrons in this system. ...
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18 views

What is a non-empirical explantation of why 1-3 methyl shifts do not occur?

How could you explain why we never see 1-3 methyl shifts? Most sources just say it is really rare, but I was wondering if you could perhaps apply orbital selection rules or a frontier orbital argument....
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47 views

The true shape of p orbitals

I'm trying to model $\mathrm{p}$ orbitals using a 3D program. What confuses me is that there are 2 shapes of $\mathrm{p}$ orbitals. I'm not sure which one is the accurate model. And what is the ...
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1answer
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Associated occupation numbers of frozen natural orbitals (FNOs) from MP2 method

The paper Frozen Virtual Natural Orbitals for Coupled-Cluster Linear-Response Theory gives the following (simplified) description of frozen natural orbitals (FNOs). In the MP2 method, the unrelaxed ...
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1answer
48 views

Can carbon have electrons in a 5d orbital? [closed]

(a) Sketch the radial probability distribution for a 5d orbital in a carbon atom. You should label the axes, but do not need to include numbers. Use arrows to indicate the radial nodes. (b) Label the ...
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1answer
129 views

The particle in a two-dimensional box model and graphene

I have been having trouble with understanding and solving the following problem. For two-dimensional conjugated systems, we may use the particle in a two-dimensional box model. In this case the total ...
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2answers
53 views

Octahedral Crystal Field Splitting Orbital Degeneracy

How are the $\mathrm{e_g}$ orbitals degenerate with each other? Note: This isn't a homework question. After the semester ended (I don't go to MIT), I ended up on MIT open course-ware to watch some ...
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1answer
97 views

What does it actually mean by stability of an atom

There are several rules related to stability of an atom, like octet rule, half filled or fully filled d orbital etc. But none of them (at my best knowledge) does not explain why an atom is stable when ...
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1answer
29 views

Octahedral Crystal Field Splitting Orbital Energy Levels [closed]

(image source) In the above diagram, where do the 3/5 and 2/5 come from? Also, how are the $\ce{e_g}$ orbitals degenerate with each other?
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1answer
660 views

Where should I publish my formula related to Aufbau Principle? [closed]

I have made a formula for determining the sequence of orbitals which is currently obtained using the Aufbau diagram. So, I wanted to know where should I publish it (if it is new). I searched the same ...
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18 views

Which orbital participates in bonding of d and f block elements as these are never the outermost orbital?

For example: Yttrium: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d1 5s2 The outermost orbital is the s-orbital but d-orbital is unfilled. How does overlap of orbital take place in YCl3 as d-orbital is beneath ...
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1answer
23 views

How value of energy of elecron becomes more negative and radius of orbit decreases with increase in the value of atomic number? [closed]

I know how energy of elecron and radius of orbit depends upon principal quantum number......But how it depends upon atomic number?
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1answer
156 views

Does an orbital have its own energy, separate from the electron? Can I picture them as a entity independent from the hosted particle? [closed]

Does an orbital have its own energy, separate from the electron? If so, is it possible for an electron to have a different energy than the orbital it occupies?
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1answer
30 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
24 views

Focusing on HOMO when discussing thermal electrocyclic reactions

When taking into consideration the outcome of a thermal electrocyclic reaction, why do we focus specifically on the HOMO of the conjugated polyene? Why does it seemingly have the highest contribution ...
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147 views

Generating hybrid atomic orbitals for Boron

My professor was showing us how to form hybrid atomic orbitals for Boron by taking a linear combination of rotated 2p orbitals and 2s orbitals (of Boron). This was done in a particular manner such ...
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1answer
89 views

Crystal field splitting of other orbitals

According to crystal field theory (CFT), $\mathrm{d}$-orbitals of central metal atom splits due to non uniform repulsion of ligands around the metal atom. Why isn't $\mathrm{p}$-orbital splitting ...
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33 views

How to graph spherical harmonics in the Mac “Grapher” application?

I was wondering if it was possible to graph the spherical harmonics in the Mac grapher app. In their manual, there is a section that talks about graphing the spherical harmonics (page 54): This is my ...
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1answer
73 views

Check My Beginner's Guide to Shells, Energy Levels, Subshells, and Orbitals [closed]

I am a beginner trying to summarize what I've learned about: Shells Energy Levels Subshells and Orbitals all at the high school level. Unlike related threads, I'm going to try to: Define each word ...
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1answer
56 views

True muonium energy levels [closed]

In a true muniom(muon-antimuon atom) do the energy levels match with that of the hydrogen's? The core is lighter for about 100 times but the muon is 100 times heavier than the electron so it would ...
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2answers
49 views

was the octet rule disproven? [closed]

so according to my understanding orbitals can hold s can hold 2 electrons and p can hold 8 electron d hold 18 and f can hold 32. wouldn't this violate the octet rule? which say only the first shell ...
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180 views

What exactly are the graphs of orbitals?

In my QM class we are finding the wave functions of the hydrogen atom. In spherical coordinates, these wave functions are functions of 3 variables: $r,$ $\theta,$ and $\phi.$ My professor stated that "...
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0answers
46 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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136 views

What is d-orbital collapse?

When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse. He describes it as a variation in energetic sequence from group 1 to 3 elements ...
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0answers
54 views

Is Tkatchenko's MBD-NL method self-consistent?

I have a question regarding Tkatchenko's [1] new nonlocal many-body dispersion method (MBD-NL). Does anyone know if it's a self-consistent method? I read this paper many times but I'm still not sure. ...
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2answers
72 views

Confusion in half filled or full filled electronic configuration

At the end of electronic configuration, we were taught that, electron orbitals are most stable when they are either fully filled or half filled. E.g., the final valence configuration of chromium is $\...
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38 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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2answers
232 views

What is the symmetry of dxy orbital?

Considering the sign of orbital and assuming the $z$-axis as a principal axis, for me, it looks like that it has two perpendicular $C_2$ axes that penetrate the lobes, so I think it is $C_\mathrm{2v}$....
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1answer
164 views

Why does 2+ oxidation state become more stable relative to 3+ oxidation state for first row of transition metals? [duplicate]

I viewed an image showing all the possible oxidation states of each element in the first row of transition metals, and the main oxidation states highlighted in a different colour. I noticed all ...
2
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0answers
42 views

Direction of electron density in p orbitals

$\mathrm{s}$ orbitals are spherically symmetric while $\mathrm{p}$ orbitals are not. For Boron, the electronic configuration is $\mathrm{1s^2 2s^2 2p^1}$. In which p orbital does the most energetic ...
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1answer
69 views

Do all single-electron species have the same orbital energies? [closed]

This picture from Ebbing's General Chemistry [1, p. 234] shows the electron orbital energies for a hydrogen atom, where each subshell belonging to the same principal quantum number ($n = 1, 2, \cdots$)...
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92 views

Why is there a big jump in first ionisation energy between sodium and potassium?

I know the trend in group 1 is that ionisation energy decreases down the group due to an increase in atomic radius and more energy levels are added so more shielding, but I'm not sure why there's such ...
2
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0answers
23 views

Carbon dioxide electronic geometry [duplicate]

It is known that allene (propadiene) $\ce{H2C=C=CH2}$ geometry is such that its hydrogen atoms are not in the same plane – do not form rectangle, but “extended tetrahedron” I wonder if structurally ...
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1answer
70 views

Why must there be degeneracy in the orbitals to have a Jahn-Teller effect? [closed]

Why is it the case that for Jahn-Teller effects to occur in transition metals there must be degeneracy in either the $\mathrm{t_{2g}}$ or $\mathrm{e_g}$ orbitals?
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48 views

What is the type of orbital depicted in this diagram?

The following image is from this answer for the question Why is one lobe of an sp3 hybridized orbital smaller than its other half?: I understood everything from that answer, but couldn't identify ...
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42 views

Force on an electron in a given orbital [closed]

I was wondering whether there is any quantum mechanical equation to describe the force on a given electron in a given orbital of an atom (lets say, for the simplest case, for hydrogen atom). Also if ...
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1answer
195 views

Sulfur can violate the octet rule because it has an “empty D orbital” is there any other information the periodic table isnt telling us?

In sulfur or any atom with an expanded octet on the 3rd row, where does the idea that they have an empty D orbital come from ?
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Bent's rule: electronegativity and s character

I'm very much confused about Bent's rule. What I perceive from it is that more electronegative element occupies a position which has less s character. What I can infer from here is that s character ...
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0answers
29 views

Properties that probe electron kinetic energy

This post is inspired by a question regarding the meaning of off-diagonal elements of the KE matrix (in some AO basis). One answer suggests that a diagonalized KE matrix might not be very useful. I ...
3
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1answer
181 views

The fifth shell of an atom [closed]

According to the $2n^2$ rule, the fifth shell should accommodate 50 electrons. However, my chemistry book says that the $2n^2$ rule does not apply to the fifth shell. Could you explain why this ...
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0answers
39 views

Is Octet Expansion appropriate when regular Octet bonding is possible (such as using dative bonds)?

I was taught to use Occam's razor whenever in doubt over an octet expansion, being told it never happened when, for example, dative bonds could resolve the issue with a regular octet. This seems to ...
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0answers
85 views

Bonding in Sulphur dioxide [duplicate]

In Concise Inorganic Chemistry by J.D.Lee (Adapted by Sudarsan Guha, Fourth Edition), on page 82, under section 3.8 - Types of Covalent Bonds (Sigma and Pi Bonds) it is given (for Sulphur dioxide ...
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1answer
120 views

Why does the d orbital size decreases on addition of electrons?

In Concise Inorganic Chemistry by JD Lee (4th edition; adapted by Sudarshan Guha), on page 80 under section 3.7 "The Extent of d-orbital Participation in Molecular Bonding" it is given: A second ...

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