The upcoming ACS national meeting in San Diego has a CHED (chemical education division) session entitled Implementing Discovery-Based Research Experiences in Undergraduate Chemistry Courses. I had previously explored what I called extreme gauche effects in the molecule F-S-S-F. Here I take this a bit further to see what else can be discovered about molecules containing bonds between group 16 elements (QA= O, S, Se, Te).

At the precise moment I write this, there is information about 108,230,950 organic and inorganic chemical substances from the World's disclosed chemistry.

Hypervalency is defined as a molecule that contains one or more main group elements formally bearing more than eight  electrons in their  valence shell. One example of a molecule so characterised was CLi ₆ [cite]10.1038/355432a0[/cite] where the description "“ carbon can expand its octet of electrons to form this relatively stable molecule “ was used.

The phenomenon of bond stretch isomerism , two isomers of a compound differing predominantly in just one bond length, is one of those chemical concepts that wax and occasionally wane.[cite]10.1016/S1631-0748(02)01380-2[/cite] Here I explore such isomerism for the elements Ge, Sn and Pb. In one earlier post, I noted a form of bond stretch isomerism that can arise from a Jahn-Teller distortion ending in two different

The geometry of cyclo-octatetraenes differs fundamentally from the lower homologue benzene in exhibiting slow (nuclear) valence bond isomerism rather than rapid (electronic) bond-equalising resonance.

I attended the first (of a proposed five) workshops organised by LEARN (an EU-funded project that aims to .. .Raise awareness in research data management (RDM) issues & research policy ) on Friday. Here I give some quick bullet points relating to things that caught my attention and or interest. The program (and Twitter feed) can be found at https://learnrdm.wordpress.com where other's comments can also be seen.

Six years ago, I posted on the nature of a then recently reported[cite]10.1002/anie.200803859[/cite] Cr-Cr quintuple bond. The topic resurfaced as part of the discussion on a more recent post on NSF ₃ , and a sub-topic on the nature of the higher order bonding in C ₂ . The comment made a connection between that discussion and the Cr-Cr bond alluded to above.

The original strategic objective of my PhD researches in 1972-74 was to explore how primary kinetic hydrogen isotope effects might be influenced by the underlying structures of the transition states involved. Earlier posts dealt with how one can construct quantum-chemical models of these transition states that fit the known properties of the reactions.

The post on applying VSEPR ("valence shell electron pair repulsion") theory to the geometry of ClF ₃ has proved perennially popular. So here is a follow-up on another little molecue, F ₃ SN. As the name implies, it is often represented with an S≡N bond. Here I take a look at the conventional analysis. This is as follows: Six valence electrons on the central S atom.

Earlier I explored models for the heteroaromatic electrophilic protiodecarboxylation of an 3-substituted indole, focusing on the role of water as the proton transfer and delivery agent. Next, came models for both water and the general base catalysed ionization of indolinones.