Talk:Pyrophoricity

Stuff

I added the list, because it seemed to me that people looking for this item would want at least some reference to the possible materials. 1diot 21:44, 9 January 2006 (UTC)

I'm wondering about the mention of methanetellurol on here -- I can't find any outside reference to it. Is there anything out there? If there are no objections, I think it should be moved to the list instead of being in the body of the article. And what are the most common pyrophoric materials? I think that should be in the body of the article. 1diot 17:08, 7 March 2006 (UTC)

I put the link back in as reference, since someone might be wondering where that specific list of materials came from. If there is a better, more-informative, concise, accesible list out there, please feel free to edit. --1diot 22:26, 3 July 2006 (UTC)

How to?

That tedious description about how to use a syringe is a "how to". Wikipedia is not a "how to" and, despite its possible usefulness, the paragraph should be removed. --69.236.33.219 05:34, 1 February 2007 (UTC)

I've removed the how-to stuff while retaining the factual kernel of the paragraph. —Eric S. Smith 17:31, 23 February 2007 (UTC)

I'm not sure about your use of autoignition temp. In pyrophoricity, oxidation occurs at a fast trate and H2 gas is normally evolved. The heat from the exothermic reaction ignites the H2. ```` —Preceding unsigned comment added by Ldmclouth (talk • contribs) 21:51, August 27, 2007 (UTC)

Sparks?

Are sparks from metals really a demonstration of pyrophoricity? My understanding is that a metal such as steel sparks not only because of the small size of the fragments created by an impact but also because of the energy introduced in the collision. If the spark was a function of the pyrophoricity of the metal when finely divided, as implied in the article, metals such as iron should spontaneously ignite when exposed to air in powdered form, which as I understand is not the case unless an outside igniton source is provided. I think presenting sparks as a demonstration of pyrophoricity is not in keeping with the general defintion of pyrophoric materials as a material which has an autoignition temperature lower than room temperature.Theseeker4 (talk) 17:17, 17 September 2008 (UTC)

Incorrect, lead and iron are also pyrophoric, when finely divided. I don't have a handy reference, only anecdotal evidence from a chemistry demonstration. I know also, that wikipedia is not a ho-to guide, especially for dangerous stuff, but lead acetate, or iron tartrate, salts of the metals with organic acids, and be roasted in a test tube, and as the organic burns away, you get a fine metal powder, which bursts into flame if exposed to air. With that description, a good quality reference may be found. Note you have to rast orgainic away, you can't grind them into pyrophoric powders.64.252.130.60 (talk) 15:52, 2 November 2008 (UTC)

I just added the dubious tag to spark testing use. I recently expanded the sparking testing article and in all of my referenced I didn't find anything that stated that the differences in sparks occur due to pyrophoricity. The only thing I found about iron pyrophoricity was here and here. Both state that iron, when in a fine form, is pyrophoric. However, that doesn't make spark testing a pyrophoric phenomenon, because the grinding wheel induces heat into the sparks/iron particles. As such I don't think spark testing is a pyrophoric phenomenon. Wizard191 (talk) 22:24, 25 May 2009 (UTC)

• The alloys which are made especially to produce sparks are known as pyrophoric and so should be mentioned here. The extent to which the heat of friction is needed to start the process of combustion will depend upon the particulars of each case. See also Angelo & Subramanian (2008), Powder metallurgy: science, technology and applications, p. 48, Powders of aluminium, iron and magnesium are highly pyrophoric in nature. Warden (talk) 11:33, 19 August 2011 (UTC)

Dead references

Both reference [1] and [3] are now dead links. :( htom (talk) 22:47, 3 February 2009 (UTC)

Diphosphane

This chemical is listed under the 'gases' section, even though the chemical's article itself lists it's boiling point as high up as 52 degrees Celsius. EgoSumAbbas (talk) 20:15, 11 August 2012 (UTC)

Silly wording.

In the list of pyrophoric materials, the following sentence appears: ...Uranium is pyrophoric, as shown in the vaporization of depleted uranium penetrator rounds into burning dust upon impact with their targets.... which is hard to take seriously since things don't vaporize to a dust (burning or otherwise). disintegrate would be a reasonable replacement for vaporize

I'm going to make the change. I am leaving the comment so that my reasoning is understood.

70.185.124.103 (talk) 05:41, 17 December 2012 (UTC) BGriffin

Removing incorrect material.

In the list of pyrophoric material, michmetal and ferrocerium are noted as being pyrophoric in bulk form.

This is not true. Ferrocerium exists in bulk form in Bic lighters and does not spontaneously burn, until it is finely divided. The same is true for michmetal. 70.185.124.103 (talk) 05:52, 17 December 2012 (UTC)BGriffin

Those two metals appear elsewhere in the list. I am removing the incorrect listings.

Antonym

This article needs an antonym or, at least, give the word that corresponds to materials that have minimal to no pyrophoricity (maybe contrast with flammability and explain the difference between pyrophoricity and hypergolicity?) Undead Herle King (talk) 23:40, 1 June 2013 (UTC)

Why?

This article, and the paragraph about water-reactive substances, don't explain why they react to the air (or water). 50.64.119.38 (talk) 11:57, 10 November 2017 (UTC)

Um

"Pyrophoric" has two definitions according to the Oxford Dictionary :

py·ro·phor·ic

/ˌpīrōˈfôrik/

adjective: pyrophoric

liable to ignite spontaneously on exposure to air.

"several boranes are pyrophoric and toxic"

• (of an alloy) emitting sparks when scratched or struck.

Unfortunately neither of them is really what chemists mean when they say it, which isn't just spontaneously but instantaneously. Even if we back off from that, some of the conditions given for the listed items are ridiculous. I worked with pyrotechnics compositions for years so I have some experience with some of them, and some from organic chemistry. Without outside influence, you're never going to get any level of fine aluminum powder down to dust to ignite in air by itself. It doesn't matter if it's 110 in the shade and humid, it isn't happening. Now, static electricity might set it off, but that's less "pyrophoric" and more "fuel air explosion" which have the important distinction of you usually being able to get away from one with your limbs intact. Likewise, sodium metal isn't doing it without outside influence. It forms a protective oxide layer almost instantly (are we going to call that combustion? technically it's the same thing with less heat) even in air thick with fog. It'll still be cool enough to pick up with gloves and cut with a knife.

Sodium isn't particularly quick to react with water directly, it's just a huge mess of molten metal flying and multiple small explosions once it does. You can walk around with a chunk of sodium in your hand all day if you're wearing a glove. It isn't going anywhere. You're also going to have trouble igniting a pile of aluminum or magnesium dust without a blow torch, although water will cause enough self heating eventually with the Mg. That's not pyrophoric behavior as anyone normal would call it. Dangerous / Flammable when wet, yeah.

Heck, even lithium aluminum hydride isn't going to do anything sitting around in dry air or even somewhat humid air (except degrade)... floating through it because of a spill or otherwise. When it hits water you'll get something instantaneous that's quite lacking in all the other materials in the list. LAH is stored under argon mainly to avoid atmospheric moisture ruining it, and the solvent system is flushed of atmosphere because most solvents LAH will dissolve in will also suck water out of the atmosphere like sponges and are ALSO insanely flammable / explosive in air. You don't want your ether to start jetting out flame when you add THF.

Lending more credibility to the non-pyrophoric nature of sodium, it was common practice that turnings were left in diethyl ether that's being stored for any amount of time to siphon up explosive peroxides that might form as well as moisture. They're probably using molecular sieves now because you don't really need a metal fire to go with your ether fire if somebody screws up and breaks the bottle near a flame, but I'm just pointing it out.

Also, Linseed oil? REALLY? The definition at the top of the article did say 5 minutes, right? It takes a lot longer than that to generate enough heat from the polymerization process to come close to igniting, and the oil itself isn't particularly flammable. It's the rags and such that are soaked in it that are the problem.

Anyway that's just my mini rant. I dare anyone to go order any of the materials off that list and haul them outside somewhere safe and just try to get them to ignite in 5 minutes from air alone. You'll need a propane torch at least for the Al & Mg dusts, nearby water for the sodium, maybe the LAH will catch fire just sitting there within 5 minutes if the humidity is ridiculous and you dump it out of the container in a pile, and you'll be waiting on the Linseed oil until the end of time if you don't soak a bunch of rags in it and cover them in sawdust. Either that or me and every other person who's messed with oil paints has been extremely lucky that their canvases don't burst into flame 3 minutes after laying out the ground color. It's a wonder all those Dali paintings could last so long with a liquid that catches on fire in under 5 minutes in air being used as a base, especially when it takes something like 50 years to fully polymerize / dry. Any second, they could have exploded into flame. I love it. --A Shortfall Of Gravitas (talk) 06:37, 27 March 2021 (UTC)