Talk:Nitrogen/GA2

GA Review

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Reviewer: Jclemens (talk · contribs) 20:04, 30 November 2016 (UTC)[reply]

Rate	Attribute	Review Comment
1. Well-written:
	1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.	~~Still thinking and discussing this~~ Fine after revision
	1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation.	Fine.
2. Verifiable with no original research:
	2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline.	Fine.
	2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose).	Fine.
	2c. it contains no original research.	Fine.
	2d. it contains no copyright violations or plagiarism.	None identified (one YouTube text mirror of our article excluded)
3. Broad in its coverage:
	3a. it addresses the main aspects of the topic.	Absolutely
	3b. it stays focused on the topic without going into unnecessary detail (see summary style).	If there's an Achilles heel in the article, this might be it, but I think we're at the maximum we can do to promote readability without losing information.
	4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.	No issues noted.
	5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.	No issues noted.
6. Illustrated, if possible, by media such as images, video, or audio:
	6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content.	~~Looking at "File:Nitrogen electrode potentials.svg", it's not clear to me why a copy of a table extracted from a copyrighted, published work can be said to be appropriately free to use.~~ (Addressed below) Everything else looks fine.
	6b. media are relevant to the topic, and have suitable captions.	Fine.
	7. Overall assessment.	Once again, detailed work to bring such a technical article to GA status!

I'm pretty sure the table copy should be okay, because you cannot really copyright data like that. Usually (like in chlorine) I put it in tabular form, but here there are many species and things are very complicated. I don't think the presentation of the data reaches the threshold of originality because arrows are pretty obvious and so is a listing by oxidation state. Double sharp (talk) 03:51, 1 December 2016 (UTC)[reply]

Sorry for the slower-than-usual progress. Keep the page watchlisted, and I'll get through it with meaningful feedback. Jclemens (talk) 18:57, 3 December 2016 (UTC)[reply]

First read through

"The extremely strong triple bond in elemental nitrogen (N≡N), the strongest bond in any diatomic molecule, dominates nitrogen chemistry, causing difficulty for both organisms and industry in converting N2 into useful compounds, but at the same time causing release of large amounts of often useful energy when the compounds burn, explode, or decay back into nitrogen gas." That's an awesome sentence, but I think it would be better as two or three.
- Done Double sharp (talk) 07:44, 4 December 2016 (UTC)[reply]
Lead is five paragraphs. Does it need to be that long? I may have more concrete ideas on that later.
- Now four. Double sharp (talk) 07:46, 4 December 2016 (UTC)[reply]
"Plant alkaloids (often defense chemicals) contain nitrogen by definition, and many notable nitrogen-containing drugs, such as caffeine and morphine, are either alkaloids or synthetic mimics that act (as many plant alkaloids do) on receptors of animal neurotransmitters (for example, synthetic amphetamines)." I'm sure there's a better way to do that with fewer parenthesis.
- Done Double sharp (talk) 07:46, 4 December 2016 (UTC)[reply]
The lead appears to cover chemical properties and periodic table position before history, while the article itself seems to address these in the opposite order. I suspect they should be ordered similarly, whichever topic is to be addressed first.
- Done Double sharp (talk) 07:42, 4 December 2016 (UTC)[reply]

History

"The discovery of nitrogen compounds has a very long history, ammonium chloride having been known to Herodotus." Awkward. Nitrogen has a long history or nitrogen compounds were discovered long ago, but a history of discovery seems an inelegant way to address the topic.
- How about "nitrogen compounds have a very long history"? Double sharp (talk) 07:40, 4 December 2016 (UTC)[reply]
"The existence of nitrogen is formally considered to have been discovered by..." formally considered by whom? This seems wordy. "The discovery of nitrogen is attributed to..." seems like it would work as well. Why does it need four citations without in-text elaboration?
- Removed the dead links (which seem to have been just repetitive), leaving just Rutherford's original paper and Weeks as a modern historian surveying it. Double sharp (talk) 07:40, 4 December 2016 (UTC)[reply]
"This "mephitic air" consisted mostly of N2, but might have included more than 1% argon." Trivia. Uncited. Of what significance? Sounds better suited to Lavoisier's article.
- Indeed mostly insignificant and would be better placed in the Ar article (along with Cavendish's astoundingly accurate statement that there was an inert component of air comprising "not more than 1⁄120th part of the whole", which turned out to be argon.) Double sharp (talk) 07:38, 4 December 2016 (UTC)[reply]
Cool to get the etymology of pnictogens here. Not sure if the term should be introduced in the lead or not, absent this explanation.
- Added the explanation to the lede. Double sharp (talk) 07:59, 4 December 2016 (UTC)[reply]
The last two paragraphs of history feel like they need expansion and maybe should be covered in detail elsewhere. These are pretty significant events that are let off with a sentence or two.

Properties

Oxygen, Fluorine, and Chlorine appear to be ordered by atomic number, since their ordering is neither alphabetical nor by Pauling scale number. Might want to make the ordering explicit.
- Since we were just talking about electronegativity, I've changed it to follow that order (Cl 3.16, O 3.44, F 3.98). Double sharp (talk) 06:27, 4 December 2016 (UTC)[reply]
"Following periodic trends, its single-bond covalent radius of 71 pm is smaller than those of boron (84 pm) and carbon (76 pm), while it is larger than those of oxygen (66 pm) and fluorine (75 pm)." Is that last 75 pm for fluorine right? Sure looks larger than 71, rather than smaller.
- Yes, my mistake: it is actually 57. Double sharp (talk) 06:27, 4 December 2016 (UTC)[reply]
"Ionic radii of 16 pm and 13 pm respectively have been published for the N3+ and N5+ cations, but these must be taken as purely notional figures as simple cationic chemistry is unknown for nitrogen due to its high ionisation energies: the first three ionisation energies of nitrogen are 1.402, 2.856, and 4.577 MJ·mol−1, and the sum of the fourth and fifth is 16.920 MJ·mol−1." Why include theoretical numbers like this, with so much commentary? We deal with theoretical numbers all the time without needing to explain that they haven't been observed in nature... at least not at such length.
- Since N³⁺ and N⁵⁺ are really just impossible, I've simply removed them and just left the ionisation energies to explain that N has no simple cationic chemistry. (Even further down the group, neither do P, As, and Sb; Bi is the first pnictogen that actually exhibits "real" cationic chemistry in Bi³⁺.) Double sharp (talk) 06:42, 4 December 2016 (UTC)[reply]
"This far to the right of the periodic table, the diagonal relationship with sulfur has with only a few exceptions faded completely into insignificance." How do I understand this without following the link?
- In the first two rows of the periodic table, elements that are diagonally next to each other (northwest-southeast) tend to be similar. For instance, the pairs Li–Mg, Be–Al, and B–Si are very similar to each other, and in fact Li, Be, and B have more in common with these diagonal neighbours than to their actual vertical neighbours. But then this drops off abruptly, with the C–P relationship being more restricted to organic chemistry (IIRC there's a book with the amusing title Phosphorus: The Carbon Copy). By the time you get to N–S, you really do not see any relationship outside the cyclic sulfur nitrides. Finally we reach the pairs O–Cl and F–Ar when there are no similarities to speak of.
- I've changed it to "Although each period 2 element from lithium to nitrogen shows some similarities to the period 3 element in the next group from magnesium to sulfur (known as the diagonal relationships), their degree drops off quite abruptly past the boron–silicon pair, so that the similarities of nitrogen to sulfur are mostly limited to sulfur nitride ring compounds when both elements are the only ones present." Double sharp (talk) 06:42, 4 December 2016 (UTC)[reply]
"14N is one of the five stable odd–odd nuclides (a nuclide having an odd number of protons and neutrons); the other four are 1H, 6Li, 10B, and 180mTa.[24]" Shouldn't the superscript before H be 2, rather than 1?
- Yes. Corrected! Double sharp (talk) 06:42, 4 December 2016 (UTC)[reply]
Do the discussions of NMR and nuclear power belong elsewhere? Should they maybe be labeled separately? Frankly, each is a bit obscure for me as a layman, and I'm not entirely sure what each paragraph means.
- These don't seem relevant to any other section since they directly relate to the different N isotopes. The NMR thing is mostly useful for ¹⁵N (which has some problems; it's used because ¹⁴N is even worse, but it is already quite bad because it's rare, and even when you enrich it you face the other problem that its signals are weak and tend to get drowned out), and the nuclear power thing is just a cool thing where one of the short-lived N radioisotopes is important (¹⁶N is formed in the water used in nuclear reactants, so if you find it outside you know immediately that there has been a leak). Double sharp (talk) 07:58, 4 December 2016 (UTC)[reply]

Chemistry and Compounds

"It is prepared by passing an electric discharge through nitrogen gas" 'It' is atomic nitrogen, right?
- Yes. Edited. Double sharp (talk) 06:43, 4 December 2016 (UTC)[reply]
"The bonding in N2 is characterised by overlap between the 2s orbitals to give occupied σ2s (bonding) and σ*2s (antibonding) orbitals (which therefore cancel out and have no net contribution to the bond order), a head-on overlap between one of the p-orbitals on each nitrogen atom to give the σ2p bonding and σ*2p antibonding orbitals, and side-on overlap between the other two p-orbitals of each nitrogen atom to form the two π2p bonding and two π*2p antibonding orbitals." This may make perfect sense to people with more chemistry background than I have, but if I've done general chemistry series within the past 10 years and can't make head or tails of the sentence even though I'm quite familiar with electron shells, I suspect it's a bit arcane and/or could be explained better.
- The idea here is to explain why nitrogen is so unreactive as N₂, which I got to at the end of the paragraph (although maybe I should have started with that at the beginning). I think a picture is badly needed... Double sharp (talk) 07:04, 4 December 2016 (UTC)[reply]
- OK, I have added an MO diagram with my lame MS Word AutoShape skills. I also added a long explanation (qualitative only: mathematically what you are doing is making linear combinations of the 1s, 2s, and 2p orbitals of each N atom, but it's easier to think of it as overlap, which is how everyone teaches it.) Double sharp (talk) 07:15, 4 December 2016 (UTC)[reply]
- Sigh...this is really hard to do without sounding like a textbook. I've reverted it to the original first, but with the diagrams showing the shapes of the orbitals (which I hope explains what "head-on" and "side-on" mean for the 2p orbitals), and the MO diagram showing the bonding. I hope it helps a little. Unfortunately I don't see a way to make it clear without hijacking it with a discussion of MO theory, so instead I've linked to that. Double sharp (talk) 07:32, 4 December 2016 (UTC)[reply]
"There are some theoretical indications that other nitrogen oligomers and polymers may be possible." And here we go again with some pretty dense theory which doesn't well explain why any of this matters.
- Well, I did write as the second sentence of that paragraph "If they could be synthesised, they may have potential applications as materials with a very high energy density, that could be used as powerful propellants or explosives." Double sharp (talk) 07:15, 4 December 2016 (UTC)[reply]

... And that's where I'm going to call it and stop for tonight. This article appears to have a larger ratio of detailed chemistry observations to practical application than Iron does. Jclemens (talk) 02:27, 4 December 2016 (UTC)[reply]

I've tried to delete a few more things (e.g. the bonding description, which is covered in the image anyway) and some of the more unstable theoretical N allotropes (they are not expected to be all that stable anyway). Double sharp (talk) 02:04, 14 December 2016 (UTC)[reply]

Continued...

So, you've done so much since last I wrote, that I'm going to back up to Chemistry and Compounds and see what I see from there. Again, I apologize for my slowness in reviewing.

It is no trouble, especially since I am currently on holiday and am editing from my phone! Double sharp (talk) 01:54, 14 December 2016 (UTC)[reply]

"In particular, since the B–N unit is isoelectronic to C–C, and carbon is essentially intermediate in size between boron and nitrogen, much of organic chemistry finds an echo in boron–nitrogen chemistry, such as in borazine ("inorganic benzene"), although the analogy is not exact due to the ease of nucleophilic attack at boron." The final clause could be made into a separate sentence and explained more fully.
- Done - I hope comprehensibly. Double sharp (talk) 01:58, 14 December 2016 (UTC)[reply]
Overall, through this whole section, I feel like I don't know enough chemistry to understand precisely what the article is describing.
I'm wondering about mixing in the practical with the chemical. The article discusses something, and at the end after less educated readers' eyes will have glazed over, discusses the practical aspects of whichever nitrogen-containing compound in a relatively straightforward manner.

I've tried to remove some of the more incomprehensible details about various N-containing compounds as ligands, leaving only that for N₂ itself. Double sharp (talk) 05:48, 14 December 2016 (UTC)[reply]

Occurrence and Production

These sections seem really, really short compared to the preceding section.
Mostly because while N has a very rich chemistry, there was never any need to come up with complex ways to extract it because air is already a 78% pure N sample that is essentially inexhaustible. There is also not much cause to make it in the lab since liquid N₂ is so easily purchased. All of this combined means that there isn't much to say. The Haber process is already somewhat off-topic as it's not making nitrogen, but using nitrogen to make ammonia. Double sharp (talk) 05:52, 14 December 2016 (UTC)[reply]

Safety

The section on Liquid safety contains elements that are substantially redundant to the preceding discussion on e.g. asphyxiation via O2 displacement.
- Addressed, I think. Double sharp (talk) 05:56, 14 December 2016 (UTC)[reply]

Overall, I think I need to go over this again, but my general impression is that there's some simple, straightfoward application text buried within an article that becomes very arcane and technical. I'm thinking about how to improve the readability... Jclemens (talk) 21:16, 11 December 2016 (UTC)[reply]

I'm still here, just with less Wikipedia time than I'd expected. I hope to give more substantial feedback over the next 48 hours. Jclemens (talk) 03:22, 20 December 2016 (UTC)[reply]

From the top again...

"Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first." This should probably explicitly state 'discovered', preferably in a non-redundant way.
Let's think about the disconnect between the lead and the rest of the article. The lead, as it stands now, is awesome and accessible; I really like how it focuses on the 'so what?' of nitrogen's effect on our lives. About the only thing I think could be added to the lead is a tidbit about laughing gas/nitrogen narcosis. However, most of the rest of the article seems to be of the "cool scientific fact with lots of detail requiring at least a chemistry minor to understand"->"Common, practical application". Can we reverse the polarity? ;-)
History, Properties, Occurrence, Production, Applications, and Safety No further comments, these are GA quality as is.
"Given the great reactivity of atomic nitrogen, elemental nitrogen usually occurs as molecular N2, dinitrogen." Is 'usually' and understatement? Would 'almost exclusively' or some similar phrasing be more appropriate, or am I misunderstanding what is meant by elemental nitrogen?
I fixed a thing or two myself. Jclemens (talk) 19:31, 21 December 2016 (UTC)[reply]

@Double sharp: to make sure he's looking at this review. Hanif Al Husaini (talk) 10:00, 25 December 2016 (UTC)[reply]

I am indeed looking and editing. It won't be perfectly understandable alas because some of these compounds (like P₃N₅) don't yet have known applications outside chemistry (research is ongoing), but I've tried to add more of those to show how nitrogen compounds are used. (I should note that if one clicks on all the links it should become possible to understand it without a chemistry degree. ^_^) Double sharp (talk) 10:02, 25 December 2016 (UTC)[reply]

OK, I think I've improved it as much as it could plausibly go with the moving of applications to the front (though perhaps it might have been a little better at the back, because if you skipped over the middle of the paragraph with the chemical information you'd only look at the beginning and the end).

I should note that the way I see it, the lede should indeed be understandable to everyone as it is the "simplified" version which everyone is going to read, but the individual sections can be more technical. I would not like cutting out useful information, even if it is only useful to the specialist, since we are supposed to cover all human knowledge, after all, and I think we'd all agree that the chemistry of nitrogen is one of the most important things to have in an article about nitrogen. Double sharp (talk) 10:16, 25 December 2016 (UTC)[reply]

I agree about the lede. I'm around tonight and will give this another go-through. Always remember that other than things mentioned specifically in the GA criteria, the rest of my suggestions are that--and you're free to disagree, propose alternatives, or say "I can't figure out how to make it any better" and if neither one of us can, then I suppose it's as improved as we can make it. Jclemens (talk) 00:48, 26 December 2016 (UTC)[reply]

OK, other than cite #53 getting broken in the editing process, I don't see any further suggestions for improvement. I didn't see an immediately obvious fix, so I'll let you address it, but that's as accessible as I think you can make it without losing info. Jclemens (talk) 01:06, 26 December 2016 (UTC)[reply]

So, looks like that got fixed and/or my cache was just broken. I don't see much more to do here, so let's call it GA. Jclemens (talk) 00:16, 5 January 2017 (UTC)[reply]

Thank you! Double sharp (talk) 02:23, 5 January 2017 (UTC)[reply]