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1500 questions
39
votes
3 answers
What is known about liquid carbon?
The wiki tells me that if you heat carbon at atmospheric pressure it eventually turns directly into a gas without being liquid first. At what pressure can you make liquid carbon? Has anyone actually ever studied liquid carbon? Surprisingly a web…
marshall
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2 answers
Why is pyrimidine less basic than pyridine?
From Wikipedia's article on pyrimidine:
Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile.
But why is pyrimidine less basic than pyridine? Pyrimidine has two $\mathrm{sp^2}$-hybridised…
CowperKettle
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39
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4 answers
Gibbs free energy-minimum or zero?
A reaction proceeds towards the direction of lesser Gibbs free energy (at constant $T$ (temperature) and $P$ (pressure)). So, we could say that Gibbs free energy at equilibrium is minimum.
On the other hand, we have $$\Delta G=\Delta G^\circ + RT\ln…
ManishEarth
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39
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2 answers
How does the silver nucleate on glass in Tollen's reagent mirroring?
I want to know the exact mechanism for how silver would start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how I see the nucleation/growth process of silver on silica:
As you can see, I didn't draw any…
victorbg
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39
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1 answer
What is a non-classical carbocation?
What is a non-classical carbocation?
How is it different from a classical carbocation?
I am confused as I have come across this term many times on Chem.SE but there seems to be nothing for my level of understanding on the Internet!
Karan Singh
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39
votes
3 answers
Why is fresh ice sticky?
Fresh ice cubes are almost instantly sticky and easily cling on to fabric and other similarly rough surfaces.
A few minutes later, however, the effect almost completely disappears.
What is the cause of this adhesion?
Why does the effect vanish…
Tabish Mir
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39
votes
2 answers
Why is gold unreactive when only one electron is in the outer shell?
I've been trying to answer my (high school) daughter's questions about the periodic table, and the reactivity series, but we keep hitting gaps in my knowledge.
So I showed that the noble gases have a full outer shell, which is why they don't react…
Darren Cook
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39
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6 answers
Why do we use helium in balloons?
While I was looking at the periodic table today, I realised that there were gases that were much lighter than helium such as hydrogen. If hydrogen is lighter than helium, why do we insist on using helium in balloons?
Ayush Madan
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39
votes
6 answers
How does ammonium nitrate explode on its own?
I thought ammonium nitrate was an oxidizer that needed to be mixed with fuel to form a high explosive (e.g., ANFO). But apparently there have been accidental explosions involving just the "fertilizer". Are these explosions also detonations? What is…
Rob N
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38
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2 answers
What exactly is hydrogen bonding (and does it really need fluorine, oxygen, or nitrogen)?
I'm not satisfied with the rationale for the intermolecular attraction known as hydrogen bonding. In my book, it states that
Hydrogen bonding is a special type of intermolecular attraction between the hydrogen atom in a polar bond (particularly H…
Greg
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38
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2 answers
IUPAC nomenclature for an interesting looking organic compound
How can I name this organic compound while adhering to the IUPAC standards?
Panglossian Oporopolist
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38
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1 answer
Why is [PdCl4]2- square planar whereas [NiCl4]2- is tetrahedral?
The molecule $\ce{[PdCl4]^2-}$ is diamagnetic, which indicates a square planar geometry as all eight d electrons are paired in the lower-energy orbitals.
However, $\ce{[NiCl4]^2-}$ is also $\mathrm{d^8}$ but has two unpaired electrons, indicating a…
user22986
38
votes
5 answers
How do I visualize an atom?
I have searched and searched, oh how I have searched.
I am looking for a 3-dimensional visualization of a whole atom, one that that includes all the orbital geometry. A proper "layered" view of the orbitals.
What I am not looking for:
Individual…
Vatsal Manot
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38
votes
5 answers
Generating neat orbitals/surfaces from molden/wfn-files
I usually use Gaussian/GaussView and don't have to bother with other programs as I think that GaussView is capable of producing nice orbital/surface pictures like this one of one of uracil's Kohn-Sham-orbitals.
But when it comes that I have to use…
pH13 - Yet another Philipp
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38
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1 answer
"Middle row anomaly" of the periodic table
I was studying about the periodic table recently, and was reading a topic associated with oxides of halogens, and came across the following line
The bromine oxides, $\ce{Br2O}$, $\ce{BrO2}$, $\ce{BrO3}$ are the least stable halogen oxides (Middle…
Rajat Jain
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