File talk:Typicalaldol2.gif

"Li" on one side but not the other?

I noticed this picture near the top of the article about Aldol_reaction. The first "reaction" shown here (actually, this also applies equally to the second one) does not look right to me. Am I reading it wrong?, or does it have "Li" (? Lithium?) on the left hand side, but not on the right hand side? What does it mean? Is it a "typo"? Could it be something to do with Lipitor? (...which is mentioned by name at Aldol_reaction -- right before this image)? How can an atom just disappear? (if we are not doing - e.g. - some kind of nuclear fission -- and, we are not)

...and, if it were (say) something involving some "linkage" to some other molecule or portion of one, like another part of a polymer, then that should be explained in the text - probably even right inside the .gif file (or at least in the Aldol_reaction article). Or, it might be a mistake; I was just wondering; any comments appreciated. and, my apologies if this is an FAQ or one that everyone "should" already know the answer to. --Mike Schwartz (talk) 23:07, 8 August 2008 (UTC)

It is lithium. It's just that organic chemists sometimes write equations that are not balanced, and even have implicit steps. The aldol reaction doesn't really produce an alcohol (aldol), but its salt, an alkoxide (which would be the lithium salt). The "implicit" step is neutralizing this salt with an acid, which produces an inorganic lithium salt as a byproduct. --Itub (talk) 20:18, 20 August 2008 (UTC)

Thank you for that helpful response. I am not sure I understand your answer (completely), but the impression I was left with, seems to be that: [A] it was indeed a case of my own ignorance, that is, where something unknown to me (but true) would be obvious to someone familiar with the field, and hence the proper target audience for this material can be considered to be limited to (only) such readers, who know certain 'obvious' things; and that [B] "Li" here does mean Lithium, but there is "more to it" than I thought; -- for example, the presence of "Li" on one side and not on the other, does not indicate any violation of "conservation of matter" here. Rather, it is a way of leaving out certain things, in order to simplify the picture, while the things that are omitted are implied, so that they are understood even though not "explicitly" stated or depicted.

Then I guess the next question to consider is, whether [S1] to try to "expand" the potential target audience of the the article about Aldol reaction, to a bigger (still not 100% perhaps?) subset of all wikipedia readers, or [S2] to just resign ourselves to doing a good job of serving the needs of those readers who are familiar enough with the field, to not require "explanations" for things that might be confusing to an outsider. Actually, I suspect that the consensus is probably for [S2]; -- otherwise, changes would have been made way before I came along. And, in fact, I probably would not have ventured in to the the article about Aldol reaction myself, if it had not been a featured article. (Here is an idea: Perhaps the entry in the log of [past] featured articles would be a good place to warn "tourist" visitors that the target audience for a given article, is only a subset of all wikipedia readers?)

I am not necessarily here to argue in favor of [S1] vs. [S2]; -- partly because [S1] might be a lot of work (work which I am probably not qualified to do); and given that our resources, [time / effort] are limited, it might well be that [S1] is not "at this time", the highest and best use of our resources [time / effort] -- even though, it might be a good item to keep on the "wish list" for later. Comments - (such as, about [S1] and [S2]) - would be appreciated. Thanks, --Mike Schwartz (talk) 23:18, 21 August 2008 (UTC)

Oh, I can see how it could be confusing to someone who's not familiar with organic chemistry. However, the way I drew it is absolutely in accordance with standard practice. When you do a typical organic reaction, you perform the reaction in some organic solvent. When it's over, you usually mix the organic solvent containing your product with some water. The water could have acid, base, or other salts in it, depending on what you want it to do. Normally, the water is there to remove any inorganic salts from the product. In the case of anion chemistry like the aldol reaction, the water also serves to protonate the product. In other words, if you were to draw the balanced right hand part of the equation, the product would have "OLi" and not "OH." Water converts the lithium alkoxide back into the alcohol. I could explain all this in the article, but I think it would confuse novices while annoying organic chemists. I hope this helps. Eugene Kwan (talk) 04:43, 1 October 2008 (UTC)

OK, thank you. It sounds like, the main cause of confusion was my own ignorance, vs. a lack of explanations of stuff that would be obvious to readers, at least those who are familiar with the field. So, I am not urging (necessarily), that something needs to be changed "at this time". However, just as an idea, if [you or] someone did want to provide some explanation, -- (maybe way in the future, when robots start to outnumber humans as readers of Wikipedia?) -- then the article Abuse of notation might serve as a good example of how to avoid "annoying" experts in the field. What the folks in the math articles do, is to put the explanation in a separate article, and then just include a little link to that, which can be ignored [not clicked on] by experts, so they don't have to be bothered. (see their example - "Abuse of notation"); (see also, Special:WhatLinksHere/Abuse_of_notation). Also, even if the "initial" material in the explanation "for beginners only" of the customs, as far as how those diagrams are drawn article, (a separate article) failed to be complete or rigorous enough when it started out, or had any other room for improvement, then [no problem!] eventually others (or - maybe the same folks) would probably step in and edit it.
(However, I understand that) explaining stuff like that, may well be far from the most pressing thing to be done at this time. Thanks for humoring me. [I inserted a colon, (":"), to "indent" your reply (above) - I hope that is OK]. --Mike Schwartz (talk) 04:07, 3 October 2008 (UTC)