I don't quite understand why the following question was closed:
Molecular structure of all periodic table element molecules exceptional cases etc
It is especially not clear to me what's unclear about it. To me it is fairly obvious, that it asks for a reference about the structures of all pure elements of the periodic table.
I admit the formatting of this question could be better and everything else a bit sharper, (and with less filling,) but I do not see how it is unclear.

Then again, maybe it is time that we talk about the scope and the tag in general. What is a reference-request and when is it considered on topic. Should we require some previous research (effort) for it? WE are certainly not here to do someone else's homework, so why impose different standards for literature research?

  • $\begingroup$ I was kind of hung up on the requested 'molecular structure' vs STP reference state structure. But then, I'm more of a materials scientist than a chemist. While I could list the stable crystal structures at STP, most periodic table charts include that already... $\endgroup$
    – Jon Custer
    Commented Sep 23, 2016 at 16:45
  • $\begingroup$ I think I noticed the helium molecule first and was like ‘what do you mean, gus?’ from there. $\endgroup$
    – Jan
    Commented Sep 23, 2016 at 16:55
  • $\begingroup$ I feel like I would have considered closing as too broad. Or, "we don't do lists on chem.SE" kind of thing. The meaning is fairly clear to me, although different people may understand it differently. $\endgroup$ Commented Sep 23, 2016 at 17:20
  • $\begingroup$ How is this too broad? There is quite a limited number of textbooks (and/or other sources) out there that cover the elemental forms of all elements. $\endgroup$ Commented Sep 23, 2016 at 17:35
  • $\begingroup$ Well, we could say "Read Greenwood & Earnshaw" but I'm afraid OP was so inexperienced that it might be not what he would prefer. $\endgroup$
    – Mithoron
    Commented Sep 23, 2016 at 20:32
  • $\begingroup$ I guess it just hasn't become much of an issue to worry about. The tag, I mean. Usually some bored guy named DEAD or TIPS would chat about it in chat, and then meta about it on meta. But it's hardly been more than an issue, and I think we shouldn't make issues for ourselves, but deal with them as they come. (The 'prevention is better than cure' sentiment doesn't apply) $\endgroup$
    – M.A.R.
    Commented Sep 24, 2016 at 18:31

1 Answer 1


I read the question few more times and I still think it should kept closed: it is still unclear to me what OP is asking.

I don't quite understand how @Martin inferred that the question is about pure chemical substances consisting of just a single element. The phrase "all periodic table element molecules" can be interpreted differently which makes the question unclear. For instance, someone else could understand the question as it is about "all molecules of all elements" (which make is severely broad, by the way). The root of the interpretation problem here is that the term "element" has an ambiguous meaning (I quote from Wikipedia)

The term "element" is used for a kind of atoms with a given number of protons (regardless of whether they are or they are not ionized or chemically bonded, e.g. hydrogen in water) as well as for a pure chemical substance consisting of a single element (e.g. hydrogen gas).

The unambiguous term "elementary substance" didn't become popular (unfortunately), so I would say it was (and still is) up to OP to clear up the above mentioned ambiguity. Interestingly, it looks like that the very tag (which currently has only one meaning of the term mentioned in its wiki1) was added by @Rubisco, and not by the OP. So, it has to be regarded as @Rubisco's interpretation which might not coincide with what OP meant originally.

1) I think this should be fixed. The tag wiki for should mention both meanings as it is done in the IUPAC Gold Book. I also think that we shall try to have IUPAC definitions quoted in all our tag wikis, but that is a different story...


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