Saturday, June 10, 2017

Visualizing #CoVFeFe

In principle, this week's blog entry should have been the end of my fun time with #CoVFeFe. But then @stuartcantrill came back with a reference to @Theresa_May:
and I realised that I had left out some vital information about the #CoVFeFe cluster: the electronic structure. Therefore, the answer to Stu's question can be short (No) or long:

The molecular orbitals of #CoVFeFe are ordered in the following way (only showing the range from -3 to -5 eV):

From this MO-levels plot, one can see the different contributions from the metals to the different MOs. I have also made figures of what the MOs look like (see below). By far the two most interesting ones are however the following two:

The left one shows a canny resemblance to the haircut of @realdonaldtrump, while right one might be seen as Donald Duck (or maybe I am the only one who sees it like this?).

Long answer:
Returning now to the question posed by Stu, the gap between the HOMO and LUMO is only of the order of 0.46 eV, which is really quite small. Too small to describe #CoVFeFe as strong and stable. Stable? Perhaps, but this is difficult to tell if one takes into account the multitude of oxidation states that would be possible for this metal cluster. Strong? Certainly not with such a small gap.

And that's it, here ends the #CoVFeFe story. At least my contribution to it. Through Twitter I have already received many comments from people that want to extend the study. Go ahead, and let me know if you have found something, so I can add updates about this fascinating new molecule (the #MoleculeOfTheYear).

Molecular orbital plots
Highest Occupied MO (HOMO)

HOMO-5, aka Donald Duck
LUMO, aka Trump haircut
The end.

Thursday, June 8, 2017

Exotic chemistry trumps nature

A few weeks ago the Twitter world was surprised by several Tweets where Chemistry played a big role. First of all, @StuartCantrill posted a cry for help:
A few days later there was a late-night typo by @RealDonaldTrump:
which was deleted the next day (but that does not work), and replaced by a challenge:

This obviously calls for a #CompChem solution, and hence I accepted the challenge and proposed a structure for the cyclic trimer livermorium (at BP86/TZ2P with Spin-Orbit ZORA as done within the ADF program):
Others immediately responded to the second challenge and proposed the solution for the "true meaning of covfefe", which should of course be written differently: CoVFeFe. Martin Stoermer (@MartinStoermer) was the first with a square planar representation of this inspirational metal cluster:
Clemens Anklin (@canklin) proposed an alternative triangular structure;
Chris Cramer (@ChemProfCramer) added in with a cry for tetrahedra to be included:
while Thomas laCour Jansen (@lacour_c) argued for a butterfly model:
And of course a simple linear molecule would also be a possibility. This leads to the following five possible structures for the metal cluster:
And of course, because these are transition-metals with partially-filled d-orbitals, this will lead to spin states:
Almost too many. Nevertheless, since I had developed a spin-state consistent density functional (S12g), the challenge just needed to be met.
And there it is. The most stable form of CoVFeFe is not square 1, not triangular 2 (which was the most popular choice in a Twitter poll), not butterfly 4, nor linear 5. No, it is the tetrahedral 3, as @ChemProfCramer and @Beleg_Doriath already predicted.
Relative energies at S12g/TZ2P (incl. ZORA scalar relativistic corrections)
All of the original data will of course be available on the iochem-bd platform.

Update June 9: Here is the link to the iochem-bd data.

What remains to be seen is whether the metal cluster could however be formed. And that is indeed the case. According to these calculations the formation of the cluster would be exothermic (-198.2 kcal/mol at S12g/TZ2P).

Update June 10: In a follow-up post I show the orbitals and a visualization of what the #CoVFeFe cluster looks like. There are two orbitals with surprising forms!

Update June 18: I have also prepared a high-resolution image to be printed on t-shirts:

That's it. Message to Donald Trump: covfefe corresponds to a tetrahedral metal cluster with a septet spin state.

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