Talk:lithium fluoride

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Discussion moved from RfD[edit]

Now I could be wrong - but I didn't think that chemical formulae were words. If we DO accept them (and I'm not really voting either way) then I have lots that I could add H2SO4 for example (if I could get the subscripts to work). SemperBlotto 10:54, 2 September 2005 (UTC)

I think the page title should be Lithium Fluoride. -- Nick1nildram 19:56, 2 September 2005 (UTC)
I'll go along with lithium fluoride with no problems at all. SemperBlotto 21:38, 2 September 2005 (UTC)
If "Li" (Lithium) is a symbol and "F" (Fluoride) is a symbol then "LiF" must also be a symbol (symbol+symbol=symbol). I would say that it's not idiomatic and is therefore no more than the sum of its parts and thus has no place in the dictionary. I would even say that Lithium Fluoride is no more than the sum of its parts. But if someone wants to add 20,000 of the things - hey, knock yourself out. Cheers, --Stranger 01:25, 3 September 2005 (UTC)
I think we should keep all symbols eg Li, F and LiF or delete them all, as I think it will always be a difficult line to draw as to what to keep and what to delete, as far as I am concerned a chemical symbol is a chemical symbol TheSimpleFool 15:36, 5 September 2005 (UTC)
H₂SO₄. But "F" isn't fluoride, it's fluorine. It's only 'fluoride' in certain combinations, like LiF (the change, IIRC, has to do with the formation of the molecule itself, not just the way it is written—but it's been years since I've studied chemistry). Actually this would be invaluable bot work to enter this kind of thing. —Muke Tever 06:44, 3 September 2005 (UTC)

Okay, there's a bit more to the chemistry as to where lines can be drawn. Clearly there's no reason to have to exclude elemental symbols such as O for oxygen. Note the distinction between that and molecular oxygen (O2) since the element O is the short-lived free radical O· by itself. Elemental oxygen also forms ozone, O3, and can be included in other molecules such as water, H2O. In fact molecules are arbitrarily complex. If you've seen the "word" for the backbone of DNA, it doesn't even fit on a page! There are several ways to write the molecular formulas (on a line of text as it pertains to this discussion) and there are also several ways that molecules are named, discussed separately.

Molecular formulas:

The simplest are chemical formulas that count the number of atoms for each element, if you can avoid balking at subscripts. An example in addition to the above is H2O2 known as hydrogen peroxide and by several other names. It is also written HOOH to show the structural formula, and this particular representation is common enough that it is a candidate for inclusion. However, structural formulas should be excluded generally because they can be rather complex, including parenthesis and bonding. A systematic formulation isn't as useful anyways because the chemistry at this level involves interactions between specific parts of the molecules, so the representations tend to be somewhat pictoral. Furthermore, not all chemicals can be written as linear structural formulas. For instance, a simple sugar can be represented as an aldehyde/ketone but not in ring form. And these so-called structural formulas by themselves are not enough to distinguish the structure of many organic compounds, for instance fructose and glucose. Structural formulas are out.
If Wikipedia were to allow chemical formulas, there would still have to be a criteria for inclusion for these. Every molecule has a chemical formula, but subscripts in the thousands defeat the purpose. In general chemical formulas become less useful as they fail to indicate structure. However, there is a middle range where this becomes advantageous to class similar molecules together. The isomers of hexane are collectively C6H14. Hexene could be written C6H12 although this more commonly refers to cyclohexane. The sugars named above are hexoses, C6H12O6. That formula could denote to a number of different compounds, but without annotation it refers to sugar.
LiF is a chemical formula, lithium fluoride formed from one atom of lithium and one of fluorine in this case. It can also be written F1Li1 under the rarely used Hill system. Flouride could be considered by itself as F-, a charged ion. H3O+ (hydronuium) and SO42- (sulfate) illustrate common formulas. Besides the components of chemical salts, ions are important to reactions in organic chemistry in the form of bases and acids in particular. Although the umbrella could be quite complex, there is a fairly clear distinction between ions present in intermediate products and the more common ones introduced as reagents. Such ions allowed on Wiktionary would be in limited number. However, it would be better to include the more complex, such as diamminesilver, in their usually expressed form, e.g. [Ag(NH3)2]+ rather than AgN2H6+.


Common names like oxydol, hydrogen dioxide, and hydroperoxide can easily be included because they were concocted as simple words. These are annoying to chemists because there can be quite a number to have to memorize and potentially confuse. The three names given are just a few of the alternatives for hydrogen peroxide. Thankfully there is a systematic naming scheme that can describe, well, anything. However, the IUPAC scheme isn't well-suited for Wiktionary. Fructose for instance is called 2,5-bis(hydroxymethyl)tetrahydrofuran-2,3,4-triol including parenthesis and commas. Although some names mimic the common names, strange nomenclature does appear for even some of the simplest chemicals. Insofar as this scheme is concerned, it is the affixes like bis-, -hydroxy-, etc. that should be included.

In summary, there is a good part of chemistry that should clearly be incorporated into the dictionary, a good part that clearly shouldn't be, and some middle ground that looks intractable but could be allowed under the right guidelines. Along the lines of SemperBlotto's original post, LiF falls under the last group. Davilla 21:15, 6 September 2005 (UTC)

a lot of this sounds like synonyms 08:36, 7 September 2005 (UTC)
See the "Attestation and the Slippery Slope" section in WT:CFI. We've covered this already in different contexts, and the current formulation seems to work just fine. If the term is used in running English text ("We then added 3 grams of LiF" or whatever), then, subject to the other restrictions in CFI, it's in. This still lets in a large number of chemical terms, but not every single possibility, and only those that actually see use. In practice, I doubt that anyone is going to go trolling through old issues of Chemical Abstracts to find new terms to plug into Wiktionary, and if they do, they're welcome to it. -dmh 15:44, 7 September 2005 (UTC)
You will note that my essay was purely informative. Effectively your post offers that any proposed chemical guidelines would be automatically derived from existing guidelines. Then as per SemperBlotto's illustrative example, there should in fact be an entry for H2SO4. (I'm curious how SO42- could be written without typesetting.) But now there's a gray area on systematic names that I'd rather see completely closed. Davilla 00:54, 8 September 2005 (UTC)
Again, I hope it'd be H₂SO₄, with H2SO4 redirecting to it. What's the difficulty with typing SO₄²⁻, now? —Muke Tever 17:34, 8 September 2005 (UTC)
  • I see no benefit to including this kind of thing. It's one thing to include the symbols for the elements, but quite another to have formulas for compounds. We can show some formulas in the descriptive text, but anything more is too encyclopedic. And we're not a chemistry textbook either. Attestation is not an issue here because most of these can probably be easily verified. Eclecticology 02:46:21, 2005-09-11 (UTC)
Isn't this just short hand notation? I would almost always write LiF in preference to Lithium Fluoride, if it can stand on its own it should be kept in the dictionary, I see it as being no different from including PCM, SDH, or USA.
Since when is USA a chemical? I have no idea what the other two are. Eclecticology 04:54:23, 2005-09-13 (UTC)
The point is that USA is not a chemical (but if it were, it would be the greatest damn chemical in the history of the world! ... U-S-A! U-S-A! U-S-A! ... um, sorry, got carried away there :-). LiF is no better or worse than USA, GiB, MHz or even pH. BTW, if you have no idea what PCM is, you could, um, look it up in Wiktionary. -dmh 04:27, 16 September 2005 (UTC)
In that case I shall lodge an {RFD} with the UN for the USA :-P

Pondering this a bit more ... One one end of the scale, it's not unheard of to see H2O scrawled on the side of a water cooler at a picnic. Similarly, terms like CO and NO2 appear regularly in air quality reports. In short, there are some terms, at the very least H2O, that are assumed to be known at least by non-chemists, if not by the general public. On the other hand, the vast majority of chemical formulae, IUPAC names, etc. appear only in contexts where the reader is expected to understand the notation. Such cases clearly do not fall under the Prime Directive of including a term if someone is likely to run across it and want to know what it means. Similar considerations would apply particularly to notations like the linear notation someone mentioned earlier. If you run across an unfamiliar formula in such a notation, you need to know the notation, not the particular term.

In this particular case, the question is, do we see LiF outside purely chemical contexts, so that someone not familiar with chemistry in general would be expected to understand what it means. Has anyone presented any such evidence? Here's what I have so far:

  • First, look up "LiF". Unfortunately (in this instance), google doesn't distinguish case. There are millions of hits, but mostly to do with other terms.
  • Look up "lithium fluoride". This is clearly a well-known material, and a very little bit of poking around shows that it's notable for its level of fluorescence (as are many fluorides, apparently ... hmmm ...). The term "ultraviolet" comes up a lot, so let's let's try.
  • Google for LiF ultraviolet (separate words). This is more promising, but spot checking shows that LiF may be glossed as "lithium fluoride", in which case there's no need to refer to a dictionary. So
  • Google for LiF ultraviolet -"lithium fluoride" to screen out cases where it's already glossed. That turns up 76,000 hits, mostly to do with building ulraviolet detectors and such.

After further spot checking, I conclude that the term LiF is used, in the expectation of being directly understood, in contexts outside pure research in chemistry. One could argue that the reader of a specification for an ultraviolet sensor could reasonably be expected to know basic chemical notation, so this particular one still seems like a judgment call. I personally would tend toward letting this one in, though without great enthusiasm, on the assumption that relatively few chemical formulae have even this level of attestation outside of chemical research. -dmh 14:09, 19 September 2005 (UTC)

OK, I'll go along with that. It seems reasonable to me that LiF should be kept, but as a redirect to lithium fluoride. Also, that we should accept similar articles for well know chemicals - NaCl etc. But, people are not going to type (or know how to type) subscripts into the "search" box; so should we have H2O and H2SO4 redirecting to water and sulphuric acid? I wouldn't object.
Oh dear. We agreed (I think) that Lif should just be a redirect to lithium fluoride. Now, someone has added NaCl with lots of description, and if I change it to a redirect I will get my wrist slapped. SemperBlotto 15:15, 15 October 2005 (UTC)