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1500 questions
26
votes
5 answers
What happens to a molecule while it is reacting?
I recently learned about the graph of activation energy that looks like this (source):
I was wondering, what actually happens to the reactants as time passes on the graph? If we were to look at the molecules when the graph was at its peak, what…
Noel
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26
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Why do the atoms in molecular models have the colors they have?
Molecular models are a great tool for visualizing a molecule in three-dimensional space. These models even appear on the web (practically every chemical's Wikipedia page), and there is a very specific color coding for atoms. After some searching I…
ringo
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26
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1 answer
Stability Comparison between the Tropylium and Tricyclopropylcarbinyl Carbocation
Why is the Tropylium carbocation less stable than the tricyclopropylcarbinyl carbocation? The tricyclopropylcarbinyl carbocation undergoes a sigma-tropic rearrangement whereas tropylium is highly stable due to conjugated system, that being, it is…
Anubhab Das
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26
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2 answers
Equivalent of Szabo and Ostlund book for DFT
Szabo and Ostlund book Modern quantum chemistry [1] is extremely useful to understand Hartree-Fock and post-Hartree-Fock methods. Not only it explains the theory behind such methods, but it is also oriented towards a practical implementation.…
user23061
26
votes
9 answers
Simple Explanation of orbitals
Imagine I was your little brother, how would you explain an orbital to him? (assuming he knows what atoms electrons and neutrons are, and the rest of the basics till that point.)
I have been reading up on this and can't make heads out tails of it.…
user20554
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26
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1 answer
Do vinyl cations adopt a classical or non-classical structure?
Whilst reading this question today, I remembered something that I had seen previously here. In the second linked question, @Martin provided a reference to suggest that vinyl cations actually adopt a non-classical structure with $\ce{sp}$…
bon
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26
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1 answer
When can a molecule be considered freely rotating at room temperature?
This question sparked from a long discussion in chat about the nature of $\ce{H2O2}$ and whether that molecule can be considered to rotate around the $\ce{O-O}$ axis (and hence display axial chirality) or not.
Considering two rather clear…
Jan
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26
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1 answer
Why doesn't the SeO2 oxidation of ketones stop at the hydroxyketone stage?
When $\ce{SeO2}$ is used to oxidise aldehydes and ketones, $\ce{SeO2}$ becomes hydrated in water, and the active reagent is selenous acid $\ce{H2SeO3}$ which oxidizes aldehydes and ketones to furnish 1,2-dicarbonyl compounds such as 9 in the scheme…
miyagi_do
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26
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2 answers
Michael reaction or nucleophilic attack at the alpha carbon of an alpha-beta-unsaturated ketone?
What conditions promote a nucleophile to undergo the Michael reaction over the nucleophilic attack at the alpha carbon of the carbonyl group in an alpha-beta-unsaturated ketone? I'm looking for an answer that considers organic and inorganic…
LanceLafontaine
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26
votes
1 answer
Why isn't the silicon analogue of benzene flat?
Why isn't the silicon analogue of benzene flat? As far as I understand, silicon and carbon make similar structures and it doesn't make sense that its benzene analogue should be substantially different.
Quoted from the article:
Chemists in the UK…
Ali Caglayan
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26
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1 answer
Can metals have a net negative charge
Normal metals like sodium or Calcium have a positive charge as $\ce{Na}^+$ or $\ce{Ca}^{2+}$.
Transition metals have a loot of variable oxidation states.
Yesterday I read about Iridium in Wikipedia and it stated that
a +9 oxidation state has been…
NeilRoy
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26
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5 answers
Comparing the stabilities of allylic, benzylic, and tertiary radicals
Which is the most stable free radical among the given species?
(1) $\ce{CH2=CH-CH2^.}$ (allyl radical)
(2) $\ce{C6H5-CH2^.}$ (benzyl radical)
(3) $\ce{(H3C)3C^.}$ (t-butyl radical)
(4) $\ce{C2H5^.}$ (ethyl radical)
The book claims the answer to be…
Dhruba Banerjee
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26
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2 answers
What makes diazo compounds so unstable and explosive?
I once had an Orgo TA refer to a diazo compound as "diazo-boom-boom" (the technical term). I have always been curious as to the reason behind the instability and reactivity.
According to Wikipedia
Some of the most stable diazo compounds are…
jonsca
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26
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4 answers
What software can calculate aqueous solution equilibria?
What software is available out there to calculate the equilibrium in a set of reactions in aqueous solution? In particular, I'm interested in software general enough to simulate things like titration curves involving acido-basicity, complex…
F'x
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26
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Why is it that every snowflake is unique?
It's pretty hard to believe in around 4.5 billion years of this planet's existence, no snowflake pattern was repeated, and that's not including potential earth-like planets.
Is there a proof to the structure or is the probability even more…
Sparkery
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