# Can we reopen the question about compound with the most diverse elemental composition?

The question What is the name of the molecule that has the greatest number of different atoms? appears to be well-defined as to what kind of answer it expects: a stable and existing molecular compound with the greatest variety in elements.

There was a recent similar question that has been deleted by OP after I suggested this question as a duplicate, so it appears to be a topic of interest. I propose the following:

• reopen the question;

• answer it in a form of contest similar to Organic Structure Challenge or synthesis golf questions using the following template:

Number of elements: 4
Compound: Alphabravocharliedeltan
Formula: $$\ce{A_aB_bC_cD_d}$$
Reference: Wikipedia/PubChem/Merck Index/Textbook/Article/…

What do you think?

• While there may well be a single such molecule documented at this time, all it takes is one suitably motivated synthetic chemist and that won't be the right answer any more. – Jon Custer Feb 17 at 21:04
• @JonCuster Labor and knowledge are necessary, but not sufficient conditions here, so I wouldn't expect a new record every month or so, which IMO is already above a suitable frequency for posting answers on SE sites. – andselisk Feb 17 at 21:19
• There could be a polymer made with like all reasonably stable elements coordinated, it's just that who would care to make it? – Mithoron Feb 18 at 19:16
• @Mithoron Hmm, a polymer composite could be made relatively easy, but you are likely talking about grafting, which is far less trivial and not every element can be easily attached to the chain. – andselisk Feb 18 at 19:23
• I thinking peptide synthesis with side chans having cryptand or other chelating group. Make about a hundred such aminoacids each with one element coordinated, polymerise and, lo and behold, you have all elements limited only by radioactivity. Cost - too high. – Mithoron Feb 18 at 19:30

I must admit I'm not really enthused by this question, as it stands.

1. The knowledge of the molecule with the most number of atoms is perhaps of passing interest ("oh, cool") but is not particularly useful to anybody.

2. Perhaps more importantly, I assume we are only counting species that have been documented in literature — otherwise it would get out of hand.

But, bearing in mind that almost any designer molecule can be made nowadays (including Very Large Things such as modified biological macromolecules or molecular machines), such a distinction is kind of arbitrary: it doesn't illustrate a fundamental scientific limit or a concept, but rather it illustrates what people have bothered doing so far.

I would suspect that whatever record we find could — at least in principle — be modified to include a new atom simply by swapping a hydrogen out for something else, for example. Thus the "record" that we find might not exactly be a triumph of scientific progress but rather a mark of where us humans got lazy (or started thinking about research that was actually useful).

But: I think we could make something interesting out of the idea of having lots of atoms in one molecule. I am very biased by virtue of my NMR background, but having many different nuclei in one molecule is (or was) of interest back in the days when NMR quantum computing was still a thing. (This, for example, led to the experimental realisation of Shor's prime factorisation algorithm.)

Instead of asking "what's the most nuclei we have ever crammed into a molecule", how about changing it to something like: "Have people specifically sought to make molecules with many different nuclei, and why would they do so / do they find use in chemistry research?"

The fundamental idea is the same, so it would satisfy the less technically inclined crowd who are happy to just go "oh wow, 10 different elements, cool!". But at the same time, it'd also be a much more useful and interesting question, in my opinion.