The molecules below were discussed in the previous post as examples of highly polar but formally neutral molecules, a property induced by aromatisation of up to three rings. Since e.g. compound 3 is known only in its protonated phenolic form, here I take a look at the basicity of the oxygen in these systems to see if deprotonation of the ionic phenol form to the neutral polar form is viable.

In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed[cite]10.1002/anie.201508249[/cite] for a synthesized molecule of ~14.1±0.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule.

Around the time of the 2012 olympic games, the main site for which was Stratford in east London, I heard a fascinating talk about the “remediation” of the site from the pollution caused by its industrial chemical heritage. Here I visit another, arguably much more famous and indeed older industrial site. The remediation of Stratford involved the removal, cleaning and returning of a vast amount of topsoil, something which was not cheap to do.

I have posted often on the chemical phenomenon known as hypervalency, being careful to state that as defined it applies just to “octet excess” in main group elements. But what about the next valence shell, occurring in transition metals and known as the “18-electron rule”? You rarely hear the term hypervalency being applied to such molecules, defined presumably by the 18-electron valence shell count being exceeded.

C&EN has again run a vote for the 2017 Molecules of the year. Here I take a look not just at these molecules, but at how FAIR (Findable, Accessible, Interoperable and Reusable) the data associated with these molecules actually is. I went about finding out as follows: The article DOI for all seven candidates was linked to the C&EN site.

A bond index (BI) approximately measures the totals of the bond orders at any given atom in a molecule. Here I ponder what the maximum values might be for elements with filled valence shells.

Another post inspired by a comment on an earlier one; I had been discussing compounds of the type I.I _n (n=4,6) as possible candidates for hypervalency.

A little while ago I pondered allotropic bromine, or Br(Br) ₃ . But this is a far wackier report[cite]10.1126/science.aao7293[/cite] of a molecule of light. The preparation and detection of dimer and trimer bound photon states is pure physics; probably considered by the physicists themselves as NOT chemistry. It is certainly true, as a chemist,  that I understood only a little of the article.

Last year, this article[cite]10.1038/nchem.2716[/cite] attracted a lot of attention as the first example of molecular helium in the form of Na ₂ He. In fact, the helium in this species has a calculated ^‡ bond index of only 0.15 and it is better classified as a sodium electride with the ionisation induced by pressure and the presence of helium atoms.

Last year, I showed photos of wildflower meadows in west London close to where we live, evolving as the seasons changed. Today we hear the announcement that London itself is set be declared the world’s first National Park City in 2019. What is a park city you may ask? It draws on the principles of National Parks such as the Peak District, the New Forest, or the South Downs in the UK, but in a city setting.

The topic of open citations was presented at the PIDapalooza conference and represents a third component in the increasing corpus of open scientific information. David Shotton gave us an update on  Citations as First Class data objects – Citation Identifiers and introduced (me) to the blog where he discusses this topic.