Unanswered Questions
1,192 questions with no upvoted or accepted answers
24
votes
0
answers
1k
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 ...
11
votes
1
answer
303
views
What is this golden looking substance?
I am currently messing around with gallium compromising aluminum. I am using a titalium lock which is just a brand of aluminum padlock and I put a gallium-indium euctic alloy on the surface of it. It’...
10
votes
0
answers
109
views
Which potentials are suitable for molecular dynamics simulation of simple explicit solvents?
Which potentials (force fields) are suitable for adequately simulating (mixtures of) explicit solvents? Interesting rheological properties include viscosity, surface tension, heat capacity.
10
votes
0
answers
20k
views
Why does the reaction of sodium nitrate, aluminium, and sodium hydroxide yield ammonia?
From Russian test problem 4301:
$$\ce{3NaNO3 + 8Al + 5NaOH + 18H2O -> 8Na[Al(OH)4] + 3NH3(g)}$$
How does ammonia evolve here? Is it that we get hydrogen gas evolving in the reaction between Al and ...
10
votes
0
answers
640
views
Identifying alkyl ligands as π-donors or π-acceptors in transition metal complexes
Is there a systematic way to identify an alkyl ligand as a π-acceptor or π-donor in a transition metal complex?
Although various sources indicate that the weak field ligands are typically π-donors and ...
9
votes
0
answers
194
views
Why are vapours of xenon hexafluoride coloured?
According to Wikipedia,
[...] It is a colorless solid that readily sublimes into intensely yellow vapors.
It is clear from the above statement that $\ce{XeF6}$ is colourless in solid form. But why ...
9
votes
0
answers
622
views
Cobalt Chloride in various solvent/water mixtures - tested
In a recent post the solvatochromic behaviour of cobalt chloride in acetone was discussed. There were some ideas how the acetone might influence the ratio between the blue $\ce{[CoCl4]^2-}$ and the ...
9
votes
1
answer
10k
views
Order of Basicity of Nitrogen Trihalides
I was asked to arrange nitrogen tri-halides in order of increasing basicity. On looking up the answer online, it turned out to be the following: $\ce{NF3}$ < $\ce{NCl3}$ < $\ce{NBr3}$ < $\ce{...
8
votes
0
answers
266
views
Why is octaoxygen diamagnetic?
I tried considering that according to LCAO-MO theory $\ce{O2}$ is paramagnetic, which is confirmed by experimental evidence. Since octaoxygen has the crystal structure in figure, I thought there is a ...
8
votes
0
answers
347
views
Isolating radium oxide
Why is radium oxide yet to be isolated when a wide range of other radium (II) compounds are known ?
7
votes
0
answers
89
views
Type of British porcelain invented around 1917-1918
Being subscribed already for 30 years on Scientific American, I recently downloaded the whole archive, and I am now going through 1914-1918.
In the 26 January 1918 issue, on page 95, there is a small ...
7
votes
0
answers
593
views
Does solvate isomers exist for coordination compounds with ammonia solvent as ligand?
I could find many sources confirming the hydrate isomerism(with water as solvent) but I couldn't find any information about any other solvent. In all the sources "hydrate/solvate isomerism" ...
7
votes
0
answers
240
views
Why does lithium aluminium hydride appear grey?
Commercial lithium aluminium hydride is a grey compound, which loses a lot of reactivity the darker it is. Luckily you can clean it up to get the reactive white compound and the separated grey ...
7
votes
0
answers
1k
views
Why isn't orthoboric acid soluble in cold water even though it has polar B-OH bonds?
This is the information I found regarding orthoboric acid's solubility:
Textbook (NCERT India): Sparingly soluble in water (didn't say what temperature - presumably cold) and highly soluble in hot ...
7
votes
0
answers
109
views
How well will molten iron chrysolite (fayalite) react with hydrogen?
The equation balances nicely, but would the reaction tend to proceed this way? What temperature and time would be needed?
$\ce{Fe2SiO4 + 2H2 -> 2H2O + 2Fe + SiO2}$
There is no problem with ...