Talk:Nitrogen

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Article changed over to new Wikipedia:WikiProject Elements format by David M, and Malcolm Farmer. Elementbox converted 12:08, 23 Jun 2005 by Femto (previous revision was that of 02:15, 18 Jun 2005).

Contents

[edit] Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Nitrogen. Additional text was taken directly from USGS Nitrogen Statistics and Information,USGS Periodic Table - Nitrogen, from the Elements database 20001107 (via dict.org), Webster's Revised Unabridged Dictionary (1913) (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table was obtained from the sources listed on the main page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.

[edit] premalignant

Sure, use that word if you want. Richard Cane 20:56, 19 May 2005 (UTC)

Thanks, Richard. Precancerous sounds amateurish, or maybe it's just me :-) JFW | T@lk 21:59, 19 May 2005 (UTC)

[edit] Is nitrogen or liquid nitrogen adding to conductor to make it superconductor and how?

Liquid nitrogen can make certain materials superconduct because it lowers their temperature, not due to any property of nitrogen itself.

[edit] uptation

tis needs to show how nitrogen is used by plants and how it can be returned if deplenished :*) Scout 21 16:01, 4 August 2005 (UTC)

[edit] nitrogen really colourless?

Well, if you see this [1] - air is supposedly slightly blue. Nitrogen being the major component of this, I would expect to be slightly blue in hue - or is this due to the water vapor? -- Natalinasmpf 01:00, 24 November 2005 (UTC)

The scientific folklore, as I remember it, claims that it is the oxygen in our atmosphere causing the blue tint. WayneConrad 20:43, 23 December 2005 (UTC)

Oxygen is blue due to the electronic configuration of dioxygen allowing a forbidden transiton to occur (electron spin inversion) which absorbs yellow light.

[edit] nitrogen tire inflation comment

The comment regarding tire inflation may be incorrect. According to the entries on Nitrogen and Oxygen, the Atomic Radius, Covalent Radius and Van Der Waals Radius are all larger for Nitrogen than Oxygen.--Osudude 16:56, 24 January 2006 (UTC)

It's definitely wrong; oxygen generally diffuses faster than nitrogen. See for example: http://www.uigi.com/noncryo.html#Membrane http://www.airproducts.com/Products/Equipment/PRISMMembranes/page01.htm


Nitrogen has a lower molar mass than oxygen (from looking at the periodic table), so the reference the Graham's law should be deleted and further explanation of why nitrogen diffuses slower than oxygen should be given.

Molecular diameter difference between oxygen and nitrogen overcomes their mass difference effect on diffusion.: http://www.sumitomoseika.co.jp/english/product/n2psa.html
My recollection is that that as the atomic number is increased, the atomic diameter decreases if the marginal electron in both elements is in the same shell. Nitrogen and oxygen both top out in the 2 p-orbital, so oxygen being the heavier of the two is smaller in diameter. Likewise flourine is even smaller in diameter and diffuse more rapidly through porous surfaces. Argon on the other hand, which is used to fill the tires of some luxury cars, is in the next period of the table, topping out in the 3 p orbitals, and thus has a much larger diameter and mass than any 2nd period element, and thus has an even lower rate of diffusion.Badocter 19:25, 25 June 2006 (UTC)

This is not a position on how nitrogen diffuses through tires vs. oxygen, but there are two problems with the current assertions. First, a proper like to like comparison should be of common air vs. pure nitrogen, not oxygen vs. nitrogen. Nitrogen is 78.08% of Earth's atmosphere, and oxygen is 21%. Tires inflated with anything besides bottled gases are already going to be over three-quarters nitrogen. Second, when comparing free nitrogen to free oxygen, the comparison should be N(2) vs. O(2) rather than N(2) vs O; in this case, is the current statement in error? ("Nitrogen molecules are larger than oxygen molecules and therefore...").

[edit] Instant frostbite?

There is a statement that liquid nitrogen can produce "instant frostbite" on contact with living tissue. That depends on what you mean by "instant." You can put a finger or even most of a hand into LN2 and semi-casually flip it around and stir it, without damage, as long as you remove it within the contact limit of about 2 seconds. The Leidenfrost effect protects you for that long, and no frostbite of skin damage is seen. It's just a bit cool. If you guage the timing correctly you can shock onlookers who've read articles like this one, but never actually fooled around with LN2 much. I know, you're going to say WP:NOR. But back at you. Got a reference for instant frostbite? And please quantitate "instant."Steve 21:45, 25 June 2006 (UTC)

The stunt is not without an element of risk as the timing is critical, and since it is done with rapid movement, there is significant risk of splashing the LN2 on one's clothes (or worse, someone elses) -- the Liedenfrost effect won't protect you if you are wearing clothes soaked with LN2 for any period of time. For instruction of proper handling of LN2: http://www.2spi.com/catalog/instruments/nitrodew-supp.html . Dermatologists often use cotton swabs dipped in LN2 for treatment of skin conditions since contact does cause frostbite and death of the top few layers of skin cells in the areas treated -- because of the speed of the treatment and low thermal conductivity of the skin, deeper tissue is not adversely impacted. Frostbite risk is documenented in the MSDS sheet for LN2: http://www.safety.vanderbilt.edu/pdf/hcs_msds/NitrogenCryo_G103_06_04.pdf . Instant is an arguably vague term, clarifying with the words " within a few seconds" is all that was needed.Badocter 03:22, 26 June 2006 (UTC)
I didn't deliberately take out the statement-- dunno what happened to it. Was waiting on concensus. Agreed that LN2 on absorbant clothes or shoes is a disaster. In derm, LN2 is applied to skin in a very different way than when a hand or finger is "dunked" in LN2. A cotton swab seems to act in freezing skin much faster than skin freezes when a finger is put into LN2. Must be a surface-area phenom.Steve 03:58, 26 June 2006 (UTC)
I might add also that the special dermatology sprayer delivers an LN2 mist which has a hugely greater surface area and heat transfer capability than a glob of liquid of the same mass, so again it acts like the vastly larger area of LN2 as you'd get on a swab. The mist really does cause instant frostbite while the glob will sizzle and airhockey slide off unprotected skin, like water on a hot tilted grill, causing no harm. So both of us are really right-- it entirely depends on the circumstances. Get LN2 on your skin in a dispersed fashion and you get instant damage. The liquid globs on bare skin without dispersion by spray or swab or clothing, or dunking the skin into straight liquid, is not instant. Steve 13:34, 26 June 2006 (UTC)
My experience with dermatologists is limited to my acne treatment as a teen, and the cotton swab with LN2 was what my dermatologist used, but that was many moons ago and I expect things have advanced since then. Best Regards.Badocter 17:44, 26 June 2006 (UTC)


[edit] Liquid Nitrogen on food?

I heard on the show Beyond Tomarrow on the Science Channel, that there's a resturant called Moto in Chicago, IL, that serves French Onion Soup with liquid nitrogen layered on top. I'm wondering, how could they do this safely? It sounds kind of risky. —The preceding unsigned comment was added by Violet yoshi (talk • contribs) .

I can assure you, if handled by trained professionals, French onion soup is absolutely safe. Oh, you mean the nitrogen… Assuming you're not supposed to actually eat it while it's cold and boiling, I'd say it's less risky than your average flambé any time. Femto 13:46, 6 July 2006 (UTC)
I didn't see the show, but I'm thinking that it was probably a joke. 161.16.0.50 21:11, 8 August 2006 (UTC)
No I saw the show. Liquid nitrogen is lighter than water and skates around on the surface of liquid water like an air hockey puck, on its own gas cussion, due to the Leidenfrost effect (this also happens when you pour it on a flat floor-- it takes off in every direction). And on water, these drops do very little but generate fog, like when you put dry ice in water. So long as you wait to eat it until the drops of liquid nitrogen are gone (fog stops forming, sizzle stops), you're fine. No more than a few seconds would be needed. You could get a nasty mouth cryo-burn before then, though, in theory. As for the soup, with small dolips of nitrogen, you can't cool it below freezing this way, until it's ALL frozen. Which obviously doesn't happen. So if it's liquid, and the nitrogen is gone, the remaining soup is above ice temp and drinkable.SBHarris 22:10, 8 August 2006 (UTC)

[edit] Nitrogen safety

Is anyone familiar with how gaseous Nitrogen kills? I don't think it works as a simple asphyxiant, i.e. that it supposedly displaces oxygen. I remember hearing from a safety guy that that's not the case; it it were, it would hurt kind of like drowning. But it's supposed to be unnoticable and painless. 161.16.0.50 20:35, 8 August 2006 (UTC)

It IS a simple asphyxiant. Drowning is unpleasant because it's not fun to have liquid in your lungs. Also because CO2 is building up, which doesn't happen when you breathe nitrogen (or any gas asphyxiant). You're low on oxygen, but can still get rid of CO2, so the sensation of needing to breathe doesn't happen. Humans have good CO2 sensors, which makes holding our breath (or being choked) very unpleasant. But we have lousy low-O2 sensors, so breating gas with no oxygen in it, hardly bothers us at all, till we black out.
That's not true of all animals! Rabbits and burrowers have very good hypoxia sensors, so "drowning" in nitrogen is very unpleasant for them. It's quite a different experience from that of humans. The question comes up occassionally in AALAS discussions of acceptable methods of euthanasia for different species of animals. For humans, replacing hydrogen cyanide gas with nitrogen in the gas chamber would be far more humane (and has been proposed, but hasn't been done, mainly for dumb historical and legalistic reasons). But don't test the system on a poor bunny!
By the way, nitrogen isn't capitalized in English. No element is. Just the symbols are. SBHarris 22:04, 8 August 2006 (UTC)

[edit] Cryogenic History

It is worh mentioning that Nitrogen was first liquified in 1883 by Wrobleski and Olzewski. (Taken from "Cryogenic Technology" edited by Robert W. Vance, published by John Wiley & sons inc. 1963)

[edit] Liquid nitrogen

Would there be any value in splitting off liquid nitrogen as a separate article similar to liquid oxygen? I'm thinking that there are sufficiently many applications of the liquid, compared with the gas. Also, cryogenics using liquid nitrogen can be more thoroughly discussed there. --Rifleman 82 10:41, 17 November 2006 (UTC)

[edit] Vandalism on Intro Paragraph

The user Takiasuu vandised the nitrogen article with the following intro paragraph:
Nitrogen (IPA: /ˈnʌɪtrə(ʊ)dʒən/) is a retarded element which has the symbol FUCK YOU and atomic number 2billion in the periodic table. Retarded nitrogen is a colorless, baldy, tasteless and mostly inert diatomic retarded at standard conditions, giving off 78.08% percent of gas into our mouths and Earth's ass. Nitrogen is a gay element of all living tissues and amino acidsand loves to have sex with the element argon. Many industrially gay compounds, such as ammonia, nitric acid, and cyanides, contain nitrogen's sperm.

I have reverted the page and added a warning to the user's talk page. --Wiki Fanatic | Talk 03:24, 1 December 2006 (UTC)

[edit] N2 in tires

Does anyone else think the claim that "Nitrogen molecules are larger than oxygen molecules and therefore, all else being equal, larger molecules diffuse through porous substances slower than smaller molecules." is juuust a bit iffy? I mean we're talking like 2 freaking picometers here. Its barely a few percent difference. I suspect that most of the difference seen in N2 and O2 loss from tires results almost entirely from O2's reactivity with the rubber. Do we at least have a source for the molecule size claim?--Deglr6328 11:25, 3 December 2006 (UTC)

[edit] Liquid to solid Nitrogen Video

I have removed the link to the video - http://www.youtube.com/watch?v=Ndbzw60fiYU.

Although this is an interesting video - the way it has been videoed is highly dangerous - and may encourage danergous repeat experiments.

Not only is the nitrogen and helium (used to solidify the nitrogen) extremely cold well under -200 degrees (this temperature if exposed to, could cause almost instant destruction of tissue - as almost showed when this investigator froze his thumb off), but there is a risk of asphyxiation if the room is not well ventilated or the liquid helium is knocked over. Also the investigators do not use appropriate BASIC safety gear - like face guard (one splash of liquid helium in the eye and you are blind), only one glove, adequate ventilation to avoid asphyxiation.

We can not on wikipedia link to this video - the screen shot is not a problem - to do so might encourage people that this is the correct way to handle these extremely dangerous chemicals.

Please either leave a comment here or on my talk page! Lethaniol 14:43, 6 December 2006 (UTC)

This is absurd, I am reinstating the video link. Wikipedia is not censored for idiots and anyone with access to liquid helium is going to know how to handle it properly and if they don't well ts that's why we have Darwin awards. The activities shown in the video are absolutely not overly dangerous. The prof did not "freeze his thumb off" and your statement that "one splash of liquid helium in the eye and you are blind" reveals that you have obviously never worked with the stuff and have little to no grasp of the fundamental physics involved with cryogenic liquids. You would not even feel a splash of liquid helium in your eye, the heat of vaporization is absurdly low, the energy contained within a paperclip at room temperature is enough to boil off something like a liter of helium if I remember right. --Deglr6328 17:36, 22 December 2006 (UTC)
I am going to put this up for Request for Comment as it is a serious issue. The fact that the people that made this video do not know how to safely handle these chemicals shows that there are idiots out there and they have access to these materials. You may be right, but I do not want to get into a revert review with this and so we need outside opinions. Thanks Lethaniol 17:51, 22 December 2006 (UTC)
I have made the link into a reference. I guess it needs a bit more text, but I am afraid if that would be according to wp:not (not a manual/safety guard). But without explanation .. then I think the link would indeed be inappropriate. Two comments, I do concur with User:Lethaniol that the video is potentially dangerous, people might want to copy it, but then, the video is on YouTube, so available anyway (question indeed is, do we need to provide a link). User:Deglr6328, no, though you are right that Wikipedia is not censored for idiots, but it has several policies which do censor information, specifically wp:el and wp:not. But then I do not yet see where these do come into play here. I'd like to hear some other opinions on that. --Dirk Beetstra T C 18:40, 22 December 2006 (UTC)

I would like to make three extra points, and then as the person bringing the RfC let others debate.

  1. The issue of linking to YouTube videos is highly controversial, see Wikipedia talk:External links, with no definite answer in sight. I think we should only add a link to videos if they really add something. Now if this was the article on phase transitions, then a video demonstrating one would be a good idea, but why one for Nitrogen phase transitions specifically.
  2. Linking to YouTube videos has lots of potential problems with copy violations again see Wikipedia talk:External links.
  3. Finally other respectable encyclopaedias would never have such links to amateur videos on such an important article.

Thanks Lethaniol 18:51, 22 December 2006 (UTC)

I am absolutely blown away by the bizzare nature of the arguments here on this topic. Who gives a toss what a "respectable" encyclopedia would do! We're not talking about some moron mixing vinegar and baking soda in a balloon here. The video is a fascinating science demo done by an actual college chemistry professor using materials and showing phase change phenomena which are exceptionally rare to see otherwise. It is the vertiable definition of encyclopedic! --Deglr6328 22:03, 22 December 2006 (UTC)
Agree. Solid nitrogen is a neat picture, and let's leave it. Liquid He is a handling hazard but not as much as you might think, due to very, VERY low heat capacity. It's damn hard to even SEE liquid helium out of tank, because if you run it though regular cryogenic hoses, enough heat is absorbed that all you get is gas at the other end. You need actual vacuum-jacketed (VJ) transfer lines. I don't think I've ever read of any body getting a liquid helium "burn" on their skin, even in these days of filling up great big MRI machine coils. I'll bet you money it's VERY hard to do. If you look up handing proceedures for handing of liquid helium, of course you get the very same boilerplate stuff you get for any cryogenic liquid handing. What do you expect? There's significantly nothing different in the language used for liquid helium. And as I KNOW how these things are written, if it was the case that liquid helium was actually a little safer to spill on the skin than liquid nitrogen (which I'm bet you it is) you wouldn't be reading that in any safety brocures, just for legal reasons. Anyway, the paranoia I see here is unjustified. If you've handled liquid helium (and I have) you can give us your personal experiences. (Mine is that you'd have a hard time getting enough together and keeping it together long enough to hurt yourself with it). You can give us any SPECIAL safety data on thermal dangers of liquid helium, if you can find it (I'll bet you can't) then post that. Otherwise, you're just making hysterical assumptions based on the idea that colder things are more dangerous, which isn't necessarily true.

And while we're at it, the same kind of thinking goes for this auto tire and nitrogen vs. oxygen thing. You might be able to take a guess at how the gases migrate through rubber, but they are so close that the experiment simply needs to be done before anybody pontificates. And since it seems to have been done, then nature and experiment rule over theory. The only question left is whether the difference seen in migration, and in oxidation, is worth paying for. SBHarris 22:36, 22 December 2006 (UTC)

[edit] Responses to RfC

  • Strongly recommend to remove picture and link to video - apart from the serious safety issue, the video is original research. There are no sources given of how to prepare solid nitrogen.  Andreas  (T) 19:02, 22 December 2006 (UTC)
If this picture is original research, then taking a picture of the Eiffel tower is also original research! They just made some solid nitrogen and took a video of it. The fact is that the melting point of nitrogen is higher than the boiling point of helium, and that is perfectly verifiable. The safety measures in the video are a bit questionable (although in my opinion the dangers of liquid nitrogen are often greatly exaggerated), but it's not wikipedia's job to censor its content for safety. The main issue I have with this picture and video is that they apparently were added only because they were "cool", but they don't add much to the article as it is. The text never refers to the pictures and vice versa; the article never mentions solid nitrogen. The same goes for the picture of the liquid nitrogen ice cream. (This could conceivably be fixed by editing the text of the article so that the pictures become relevant and useful.) Itub 20:09, 22 December 2006 (UTC)
I am rather surprised at this view! First of all, I don't see how it is "original research" at all. I didn't make the video number one, and two, there is no "research" involved here. Its just a science demo. It is common knowledge that nitrogen freezes if you lower its temperature enough. I did not add the image "just because it was cool" (ha-ha) but because it is VERY rare to see solid nitrogen ice anywhere. It is NOT something one regularly encounters even if you are familliar with the liquid. I really don't see the need for the text to refer to the image. The entire page is about nitrogen! Its self explanatory with the caption. --Deglr6328 21:51, 22 December 2006 (UTC)

I viewed the video and I don't see much of a problem. Safety rules are safety rules but ... in real life, you can get away with quite a bit. I agree with the above Deglr6328 that if you can access liquid helium, you should know how to handle it safely. Seeing solid nitrogen is actually rather interesting and encyclopedic. It would be perverse if a floating frog were notable and solid nitrogen were not. --Rifleman 82 20:24, 22 December 2006 (UTC)

CLARIFICATION - I think at least one person got the wrong end of the stick - this is not about the PICTURE of the solid nitrogen, but the link to the VIDEO from YouTube. I do not think anyone will have a problem with a picture of nitrogen, only maybe whether it is interesting or not. Lethaniol 22:58, 22 December 2006 (UTC)

Reccomend removing link to video and picture for the following reasons:

  1. They're original reasearch
  2. Youtube is generallly not used as a source because it's very unreliable
  3. Health and safety considerations

--Redlock 02:49, 25 December 2006 (UTC)

  • I think the video nicely illustrates some of the properties of liquid nitrogen. One YouTube user even commented wikipedia rediected me here. good vid, useful on the topic im doing for my project. The Wikimedia projects (including Wikipedia) contain all sorts of information that could be dangerous—Wikibooks has explicit instructions for how to manufacture acetone peroxide, the explosive used for the 7/7 bombings. This is tame compared to that. People are going to find this stuff on the internet, with or without Wikipedia. We might as well keep it. Strad 17:21, 27 December 2006 (UTC)
  • I would agree that it is an intersting video. Based upon the lack of health and safety shown in the video, I would suggest that this leaves the question of how reliable the rest of the vidoes content is. Adambro 19:36, 1 January 2007 (UTC)
  • The video seems to be able to inspire people to use no lab safety (except for the one glove). I agree that some fault goes to the person who attempts it if by attempting it he/she freezes a finger off etc., but some fault would also go to the link to the video (thus to this article) for giving that person a chance to get "inspired" by the video. Slartibartfast1992 02:55, 3 January 2007 (UTC)

Wow what a tough one! On the one hand I whole heartly believe that everyone should be entitled to access information, but on the other hand the fact that this is a you tube video and that it demonstrates a particularly dangerous experiment is troublesome. However to settle the dispute I've discovered that the Anarchist Cookbook is available on wikipedia with a link to where it can be downloaded. Thus, it would seem the precident of allowing access to dangerous materials is acceptable.

So, leaving out the fact that it's dangerous I feel the next issue is that it's hosted on you tube. Since you tube is fairly stable (read, google bought it, it's not going anywhere) I believe the link should stay. Perhaps we could put a disclaimer next to the link stating that it's not done safely and "should not be tried at home"? Something to that effect would get the message across!--Robert Stone, Jr. 03:35, 5 January 2007 (UTC)

The video does NOT contain original research. How many times do we have to go over this? It has been known for a century now what effects liquid helium has on other materials and the freezing point of nitrogen has been known even longer. The demo they are doing is NOT THAT DANGEROUS! Its probably about as dangerous as the preparation of a spaghetti dinner. Spilling boiling water on your skin WILL burn you instantly. Spilling liquid nitrogen on your skin will not burn you for a few seconds because of the leidenfrost effect and the fact that nitrogen has a very low heat capacity. In fact, I am going to take a picture of me pouring liquid nitrogen on my hand and add it to the article just to wig everyone out.--Deglr6328 12:22, 7 January 2007 (UTC)

But do add the disclaimer that this should not be tried any place other than fairly smooth skin. And keep the LN2 as liquid-- no misting or application with, or to, cloth or high surface-area stuff. The Leidenfrost effect works great, but only in the right circumstances. Pour liquid LN2 on your hand-- no damage. Pour it on your sneakered foot or a sock, you've got a problem. Get sprayed with mist, you're burned, etc. SBHarris 16:50, 22 January 2007 (UTC)


It's clearly encyclopedic, and better for the article than for phase transition. Agree with Robert Stone. — Sebastian 06:57, 22 January 2007 (UTC)

[edit] Fact tags about nitrogen and oxygen size and diffusion

I disagree with the User:Beetstra's removal of the fact tags I added to the nitrogen article.[2] The first one can't be explained away by the next sentence, especially when the next sentence is also questioned! Let's start with the second fact tag: Beetstra says that it is based on the infoboxes. What in the infoboxes? If you just look at the atomic radius, you are using it out of context, because air does not have atomic N and O, but N2 and O2. The nitrogen molecule has a triple bond, which is considerably shorter than the double bond in the oxygen molecule (110 vs 121 pm, according to the table in chemical bond). Therefore it seems more sensible to say that N2 is smaller, unless a solid reference can prove otherwise (maybe for some reason I cannot fathom, N2 has a larger "effective" diameter, even if the bond length is shorter, but in that case, where is the reference?). Second, the statement that N2 diffuses through rubber slower than O2 needs some solid evidence, regardless of which molecule is larger. I was going to delete the whole paragraph because I suspect it is an urban legend, but I decided to take the gentler approach of adding the fact tags. I'm readding the tags for now. (I don't dispute that sometimes tires are filled with N2, just the explanation.) Itub 20:51, 22 December 2006 (UTC)

I concur, the second fact decides the faith of the first. But as far as I know, there are (at least) two things in play here. Diffusion is dependent on size and weight. The size is bigger (we are looking along the bond now) where bond length is not of a real effect. But OK, a reference for the van der Waals radii of the two molecules would be nice. Secondly, nitrogen is a heavier atom than nitrogen. That makes diffusion slower (the molecule absorbs more energy on impact). I will leave it for now, see how it develops, but I do think the story is correct (it would probably be better to fill the tyre with argon or xenon, anyway). --Dirk Beetstra T C 21:15, 22 December 2006 (UTC)

Ok, I think I found an interesting reference, presented in an American Chemical Society Rubber Division technical meeting: Effects of Nitrogen Inflation on Tire Aging and Performance. The authors place most of the emphasis in tire aging due to oxidation, along with better pressure vs temperature dependency due to lack of moisture. Regarding permeation, they say: "One benefit of using N2 is claimed to be higher air pressure retention because of the lower permeability of N2 than O2 through IIR, NR, and SBR compounds. While this is true in controlled laboratory tests of pressure retention in tires, the benefit to the real world consumer could be somewhat less. Pressure loss due to leakage around the rim flange seal of the tire to the rim and also the valve seal to the wheel (plus pressure loss through the valve itself) could account for some of the air loss experienced by the typical consumer, for example." Note that they don't say anything about N2 molecules being bigger, and that they treat this as a "claim". I could believe that N2 permeates slower than O2 through rubber because this permeation is not an ideal process (like an ideal gas going through a pinhole), but there is some interaction between the gas and the rubber. Itub 22:04, 22 December 2006 (UTC)

Talking to myself here. I found this paper called The Permeability of Different Rubbers to Gases and Its Relation to Diffusivity and Solubility (full text requires a subscription), and it convinced me that yes, oxigen permeates rubber faster than nitrogen. Also, it is actually true that N2 is bigger than O2, according to a specific definition of molecular diameter based on "internal friction"! As SBHarris said above (as well as the paper on effects on tire aging), there's still the question of whether this is worth paying for, but it turns out that it is a real effect. Sorry if I was too critical, but I think the net effect will be positive: we will have some references to back up these statements. Itub 22:55, 22 December 2006 (UTC)
Sorry I did not answer earlier, I was busy with hydrides and hydrogen sulfide.
No probs about being too critical, maybe I was not critical enough here. And well, it never hurts to have references to back it up, anyway. It is just, normally these tags get added, and noone looks after them, until people start deleting the statements, even while they are true. I see by the way, that I made a mistake earlier, of course oxygen is heavier than nitrogen, which would make oxygen a slower diffuser than nitrogen (purely on molecular weight effects). I guess I need a holiday (less than two days to go)! See you around! --Dirk Beetstra T C 23:02, 22 December 2006 (UTC)


[edit] melting point -210.00'C, boiling point -195.75'C

Is this correct? —The preceding unsigned comment was added by 84.202.209.246 (talk) 13:06, 21 February 2007 (UTC).

this is very important

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