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1500 questions
21
votes
2 answers
Jahn-Teller Distortions in Square Planar Complexes?
A Jahn-Teller distortion is predicted whenever a non-linear symmetric molecule has degenerate orbitals and has unequal electron occupation in those degenerate orbitals. Of course, this most often is discussed in the context of octahedral complexes,…
Geoff Hutchison
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21
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1 answer
Why does tin form tin (II) compounds?
The stability of the +II oxidation state in lead has been widely attributed to the so-called “inert pair effect”: the 6s subshell is stabilized through relativistic contraction due to the near-c speed of its electrons. Now, Pekka Pyykkö states in…
Corundum
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21
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4 answers
Addition of HOBr across C=C
Source: Carey Advanced Organic Chemistry B, problem 4.1 b
Looking for interesting problems about addition to C=C, I came across this in the back of Carey. It looks like a simple addition across the alkene, but using HOBr which is something I've…
NotEvans.
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21
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1 answer
Can we use phosphorus triiodide in Hell-Volhard-Zelinsky reaction?
Using the Hell–Volhard—Zelinksy (HVZ) reaction, we can get alpha-chloro or alpha-bromo carboxylic acids:
Is it possible to similarly make alpha-iodo carboxylic acids with the help of HVZ reaction? I could not find any reference of HVZ reaction…
Nilay Ghosh
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21
votes
7 answers
What is the difference between an element and an atom?
First, I would like to quote sentences from a book introducing elements and atoms:
An element is a fundamental (pure) form of matter that cannot be broken down to a simpler form.
Elements are made up of particles called atoms. An atom is the…
Jeffery
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21
votes
3 answers
What makes oceanic desalination so expensive?
What specifically makes oceanic desalination so expensive?
Lora Wesley
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21
votes
1 answer
Why is gum so sticky and what chemicals make for easy removal of gum?
To give this question context, I work in a restaurant and sometimes I'm in charge of getting all of the gum off of the tables at work. Don't mind the work, but I'd be interested in hearing what makes gum so sticky and if there is any chemical I can…
nick
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21
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3 answers
A monocyclic 6 carbon ring with 6 double bonds
I would like to know if this molecule has ever been synthesized, if not why not, and what would its IUPAC name be?
Blackness
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21
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1 answer
What causes the iridescent colour in laboratory grown bismuth?
Artificially grown bismuth crystals are arguably magnificent, as seen in the image below:
Image source: Minerals.net
The website states that:
They have hopper-like growths in pseudocubic crystals and are usually coated with chemicals to prevent…
user15489
21
votes
5 answers
Strength of hydrogen bonding in phenol or methanol
I wanted to know whether hydrogen bonding is stronger in phenol or methanol.
I saw on Wikipedia about the enthalpies of hydrogen bonding in various cases.
but could not find the answer to this question of mine.
I also want to know whether the…
Sugandha Gupta
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21
votes
4 answers
What is the origin of the maximum in rotational heat capacity?
The graph of rotational heat capacity above shows a small maximum before approaching the equipartition value. What is the origin/physical explanation of this maximum?
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21
votes
5 answers
What is SPDF configuration?
Recently in my chemistry classes, the teacher spoke about SPDF configuration and then said that we'll be taught about it in higher classes.
But I'm sorta curious to know that what is SPDF configuration and is there something like - obtaining…
Anoneemus
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21
votes
2 answers
Why does solubility of solids sometimes decrease with temperature increase?
Recently I was researching $\ce{Ca(OH)_2}$, and I found this on Wikipedia:
\begin{array}{|c|l|}\hline
{\rm \color{blue}{Solubility~in~water}}
& {\mathrm{0.189\,g/100\,mL}\ (0\,^\circ\mathrm{C})} \\
& {\mathrm{0.173\,g/100\,mL}\ …
ParaH2
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21
votes
1 answer
Do only outer electron shells take part in forming chemical bonds?
Do only outer electron shells take part in forming chemical bonds? Or could an inner shell create a bond under some conditions?
Dirk Bruere
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21
votes
4 answers
Why is ligand substitution only partial with copper(II) ions and ammonia?
When studying ligand substitution (at UK year 13 level), the following example has been given:
\begin{align}
\ce{[Cu(H2O)_6]^2+ + 2NH3 &<=> [Cu(OH)_2(H2O)_6] + 2NH4^+}\\
\ce{[Cu(OH)_2(H2O)_4] + 4NH3 &<=> [Cu(NH3)_4(H2O)_2]^2+ +2OH-…
Ivan
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