This post arose from a comment attached to the post on Na ₂ He and relating to peculiar and rare topological features of the electron density in molecules called non-nuclear attractors. This set me thinking about other molecules that might exhibit this and one of these is shown below.

I analysed the bonding in chlorine trifluoride a few years back in terms of VSEPR theory. I noticed that several searches on this topic which led people to this post also included a query about the differences between it and the bromine analogue. For those who posed this question, here is an equivalent analysis.

On February 6th I was alerted to this intriguing article[cite]10.1038/nchem.2716[/cite] by a phone call, made 55 minutes before the article embargo was due to be released. Gizmodo wanted to know if I could provide an (almost) ^† instant ^‡ quote. After a few days, this report of a stable compound of helium and sodium still seems impressive to me and I now impart a few more thoughts here.

The story so far. Inspired by the report of the most polar neutral compound yet made, I suggested some candidates based on the azulene ring system that if made might be even more polar. This then led to considering a smaller π-analogue of azulene, m-benzyne. Here I ponder how a derivative of this molecule might be made, using computational profiling as one reality check.

This is one of those posts of a molecule whose very structure is interesting enough to merit a picture and a 3D model. The study[cite]10.1126/science.aal1619[/cite] reports a molecular knot with the remarkable number of eight crossings.

Here is an inside peek at another one of Derek Lowe’s 250 milestones in chemistry, the polymorphism of Ritonavir .[cite]10.1023/A:1011052932607[/cite] The story in a nutshell concerns one of a pharma company’s worst nightmares;

The previous posts produced discussion about the dipole moments of highly polar molecules.

A project fork is defined (in computing) as creating a distinct and separate strand from an existing (coding) project. Here I apply the principle to the polar azulene 4 explored in an earlier post, taking m-benzyne as a lower homologue of azulene as my starting point. m-Benzyne is a less stable 1,3 isomer of o-benzyne (1,2-dehydrobenzene), and is often represented as a 1,3-biradical of 1,3-dehydrobenzene.

I am completing my survey of the vote for molecule of the year candidates, which this year seems focused on chemical records of one type or another. The first article[cite]10.1002/chem.201601916[/cite] reports striving towards creating a molecule covering a complete column of the period table.

This, the fourth candidate provided by C&EN for a vote for the molecule of the year as discussed here, lays claim to the World’s most polar neutral molecule (system 1 shown below).[cite]10.1002/anie.201508249[/cite] Here I explore a strategy for extending that record.