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1500 questions
14
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2 answers
Why does benzyne dimerise and not trimerise?
Why does benzyne prefer to undergo dimerisation to stabilise itself, even though the product formed (biphenylene) is anti-aromatic?
Why does it not undergo trimerisation through the following pathway, resulting in an aromatic and presumably more…
Ayushmaan
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14
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2 answers
Is there an iron–iron bond in diiron nonacarbonyl?
Diiron nonacarbonyl, $\ce{[Fe2(CO)9]}$, is often depicted with an Fe–Fe bond as shown at the left-hand side:
The Fe—Fe bond is usually invoked in order to (1) explain the observed diamagnetism and (2) satisfy the 18-electron rule. However, I'm also…
orthocresol
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14
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1 answer
Thermal stability of alkali metal hydrides and carbonates
Why is it that thermal stability of alkali metal hydrides decreases down the group, but for carbonates, it increases?
I used Fajans' rule to check for ionic character but somehow this is only applicable for carbonates.
Avyansh Katiyar
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14
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1 answer
Trustworthiness of IC50 values
My two questions: Is replication of recording $\text{IC}_{50}$ values prior to (primary?) publication less common than performing a reaction several times to determine a more reliable record? Provided the very small quantities used in these tests…
Buttonwood
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14
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6 answers
What is a "hydrogen-like" or "hydrogenic" atom?
I'm studying some chemistry on my own in anticipation of the new school year and in my book, I came across the Rydberg equation for the first time. I worked through some examples and everything was fine until I came across this comment on the…
Melanie Shebel
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14
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3 answers
What chemical properties make LSD so psychoactive?
Lysergic acid diethylamide (LSD) is a well known hallucinogen and (usually) illegal psychoactive drug with the structure below:
The drug is active is doses measured in micrograms in contrast to many other active compounds where the dose is…
matt_black
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14
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2 answers
Etymology of "click chemistry"
According to Wikipedia, the term click chemistry was coined by K. Barry Sharpless in 1998.
What does the word 'click' mean here? I guess it means "join" here but I'm not sure.
user48852
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14
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2 answers
What is metamerism
According to metamerism in polyvalent functional groups, if both alkyl groups' around functional group are different then they are considered as metamers but in few books it is given that if one of the alkyl group is different then it is a…
Arvind Tiwari
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1 answer
Is Orca wrongly breaking bonds? Why can it only optimize the molecule with COPT activated?
I would like to ask for help in using Orca (v. 4.0.0) for conducting a simple optimization.
First I have this structure (primarily optimized using MMFF94s force field on Avogadro):
Thus I tried to conduct a simple optimization by using Orca and…
Manoel Barrionuevo
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14
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2 answers
Which is a better nucleophile: hydroxide anion or amide anion?
I know that nucleophilicity order depends on what type of solvent we take, polar protic or polar aprotic and also on the basicity of nucleophile.
In DMF, which is a better nucleophile $\ce{NH2-}$ or $\ce{OH^-?}$
Since the solvent is aprotic polar,…
user157725
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14
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2 answers
If I drink water without sipping, is there a chance of saliva diffusing into my bottle?
I always prefer to drink water without sipping, like this:
I do this so that my saliva doesn't contaminate the water contents, which would make the water impossible to share with my friends.
But lately, I have been thinking: Can the saliva diffuse…
Pritt says Reinstate Monica
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14
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1 answer
Using group theory to make molecular orbital diagrams
Because of Orthocresols' meta post I ask this question about application of group theory to molecular orbital theory.
In my undergraduate lecturers, we've seen many examples of making qualitative MO Diagrams by inspection of what orbitals could…
James Dealon
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2 answers
Transforming AO basis electron repulsion integrals into molecular spin orbital basis?
I am attempting to do project 5 on Daniel Crawford's Group's GitHub. I'm having some trouble reproducing the MP2 energy, which is given in project 4.
In project 4, the MP2 energy is given as:
$$ E_{MP2} = \sum_{ij}\sum_{ab}…
iammax
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14
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1 answer
Does a chiral centre have to have 3 or 4 different groups attached?
I am seeing conflicting answers on the net
e.g.
A carbon atom is chiral if it has four different items bonded to it at the same position. (Wiki)
compared to
Stereocenter (chiral center): An atom with three or more different attachments…
K-Feldspar
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14
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2 answers
Will a solid object lose or gain atoms on standing over time (without being acted upon by external influences)?
Suppose I'm in my room with my keyboard, my desktop and my desk. Are these objects losing or gaining atoms every second? Or are they forever stuck with the same number of particles until you scratch, break or pulverize them?
Or suppose, for…
Gabriele Scarlatti
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