Talk:Hydrogen cyanide

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Fruit pits[edit]

How much hydrogen cyanide is in the pit of cherries and such? Less than 300 parts per million? Like, if you ate like 10 pits of cherries, would you become cyanide poisoned? Or is it a different, non-poisonous, say, ion? ugen64 23:56, Nov 19, 2003 (UTC)

100g of pits (as I wrote) will yield ~10mg of HCN. 19:42, 22 December 2006 (UTC) — Preceding unsigned comment added by Douglas Bradford Oliver (talkcontribs) 19:42, 22 December 2006‎ (UTC)


I don't believe that Prussic acid can be synthesized from ammonia and carbon monoxide, but I'm a first year chem student so I'm not exactly an expert in the field. Someone should check on that (and by "check on" I don't mean try at home!) —Calmofthestorm 17:59, 16 Jun 2004 (UTC)

A google search seems to agree with the article, and I believe that it is correct.
P.S. Since you're a first year chem student, try to start using the IUPAC names for chemicals. You'll still be served well by knowing what Aqua fortis, Oil of Vitriol, Muriatic acid, slaked lime etc. are, but try to avoid using archaic names for chemicals.
You should also sign your posts with "~~~~"
Darrien 18:36, 16 Jun 2004 (UTC)

The article cites the Andrussov process as a production method of HCN, but gives the chemical formula:

CH4 + NH3 + 1.5 O2 → HCN + 3 H2O

This is not the empirical formula. It would work on a molar basis, but I'm pretty sure that the correct formula for the balanced reaction should be:

2 CH4 + 2 NH3 + 3 O2 → 2 HCN + 6 H2O

I'm an engineering student who's only had the prerequisite freshman chemistry courses, but I'm pretty sure that you can't have half of an O2 molecule in a reaction because O- is an entirely different beast. Am I wrong on this one?

ianrox 17:01, 1 Jun 2006 (UTC)

Either equation is fine but expert chemists like to minimize the multiplyiers preceding the formulas. When a chemist writes 1.5 O2, we are not considering subdividing molecules (!) but subdividing moles (ca. 6 x 10exp23 molecules!). Your question is excellent, I wish that more folks tried as hard to decipher the language of chemistry.--Smokefoot 17:22, 1 June 2006 (UTC)

Empirical formulas are the easy part. I definitely understood what the reaction meant, it was all just a technical foible in my eyes. Chemical equilibria are the parts that got me. ianrox 14:47, 1 Jun 2006 (UTC)

It has been some years since I studied chemistry, so perhaps there have been new discoveries or new terminology of which I'm unaware. The words about the "process used at BASF" say that the reaction yields hydrogen cyanide and ammonia. Can that be right? The equation shows HCN and H2O, which back in my time always used to be water. Snezzy 18:53, 15 January 2007 (UTC)

Hasn't changed in the last couple of years, I changed the wording. --Dirk Beetstra T C 18:58, 15 January 2007 (UTC)


Hi. I added a section about the use of cyanide by the Nazis. I think it's appropriate, but if anyone doesn't like it, let me know and we can discuss. Perhaps some additional facts about who first isolated the chemical or what-not could tone it down if desired. LMK --DanielCD 20:31, 27 Jul 2004 (UTC)

Of course it's appropriate, it would be inappropriate not to mention it in an encyclopedia. E=MC^2 T@lk 00:45, 19 May 2005 (UTC)

i don't think it is appropriate, especially since you did not provide references or sources for your information. Keep to the technical facts of science and leave the politics. propaganda, and controversial aspects to another forum.Kenny56 05:24, 7 January 2006 (UTC)
The fact that the Nazis used HCN to kill is not politics, propaganda, or controversial. It is factual history. --Squiddy | (squirt ink?) 10:58, 7 January 2006 (UTC)
Then it shouldn't be any problem for you to cite the sources of these "facts", right? Please provide references to back up your claims. The link that you provided does not seem to exist. Kenny56 16:26, 7 January 2006 (UTC)
Any history book on the Holocaust provides this info. Use of HCN at Auschwitz is beyond doubt. It is too widely known to need a ref on the page. The link I added was about the Iraq-Iran war. --Squiddy | (squirt ink?) 16:32, 7 January 2006 (UTC)
This is true. It was in the form of an insecticide marketed under the trade name Zyklon B. – ClockworkSoul 19:16, 7 January 2006 (UTC)
"It is too widely known to need a ref" - what the heck humor me with the ref anyway, seeing as it is so well known.— Preceding unsigned comment added by (talkcontribs) 14:41, 6 November 2006‎ (UTC)

If its you don't believe the Nazi's used HCN, go find your own ref! —Preceding unsigned comment added by (talk) 03:20, 9 January 2009 (UTC)

Weapons claims and reports[edit]

Reports that lack sources or citations are considered dubious at best, and approach propaganda in their worst form. Please do not make claims without providing references for verification.Kenny56 05:36, 7 January 2006 (UTC)

  • Of what do you refer, specifically? – ClockworkSoul 15:12, 7 January 2006 (UTC)
The three sentences under a section about use as a chemical weapon. Please provide verifiable citations for statements and claims of facts, otherwise the information is dubious and has no place in an encylopedia.Kenny56 16:33, 7 January 2006 (UTC)

Iraq's alleged use of cyanide[edit]

I believe you have Iraq as using cyanide - according to the US Army War College it was the Iranians.— Preceding unsigned comment added by (talkcontribs) 19:49, 1 March 2006‎ (UTC)

On the above point - why is the article left incorrect? Pellitiere ( Army War College in PA ) researched this many years ago and reported that it appeared the Iranians accidentally killed civilians with their cyanide based gas - Iraq used mustard gas at the time.— Preceding unsigned comment added by (talkcontribs) 14:39, 6 November 2006‎ (UTC)

Hydrogen cyanide + tobacco smoke = foul taste in mouth?[edit]

quote: “Hydrogen cyanide forms a foul-tasting compound when it combines with tobacco smoke. For this reason, some chemists choose to have a lit cigarette in their mouth while they are working with it, as they receive an early warning against possible cyanide poisoning."

Can you give a source? Or is it a personal observation of the author or a habit of a chemist the author knows? I’ve never heard that but it sounds interesting.— Preceding unsigned comment added by 212.42.236 (talkcontribs) 23:32, 22 July 2006‎ (UTC)


Can anyone tell me if HCN gas is corrosive to mild steel? It doesn't appear to be, but I know that CN- behaves much like a halogen ion, and HCl and HF are very corrosive to steel, right? Thanks —Preceding unsigned comment added by (talkcontribs)

Both HCN and HF are molecules in the pure form, and then not corrosive (you can pump HF through a steel pipe without reaction). If there is water available, they become corrosive, and then the corrosivity is depending on a) the pKa of the acid and b) the stability of the salts formed (a.o determined by lattice energy), some combinations of metal-cations and certain anions are particularly stable, thereby driving the reaction; some metals do not dissolve in strong acids like sulfuric acid or nitric acid, or even aqua regia, but do dissolve in dilute HCN) --Dirk Beetstra T C 18:42, 24 August 2006 (UTC)

Still propaganda in a Wikipedia science article[edit]

This afternoon I used this Wikipedia article on hydrogen cyanide in an internet post because HCN's spectral signature was found in observations of the unusual Kuiper Belt object 2003 EL61. I was annoyed to see unfounded accusations included in this chemistry article. It has not been proven that "Iraq gassed the Kurds". Iraq denied this claim. Plausible evidence has been provided that another party did this, specifically Iran.

This information is in no way appropriate to an article about chemistry. I consider it politically motivated vandalism. If one wishes to make such accusations, then that person or group needs to create an article about it. I believe in this case that such articles must surely already exist on Wikipedia, it might be appropriate to link to such an article, but injecting propaganda into a science article is abhorrent. It gives the propaganda unwarranted credibility by masquerading as "Science".

What definitely identifies this as propaganda is that only two actors are accused, German Nazis and Iraqi Ba'athists. Many tonnes of poison gas were used in World War I and I would be surprised if there weren't others involved in the use of hydrogen cyanide as a chemical weapon in history.

Mike Emmert 20:18, 26 August 2006 (UTC)Michael C. Emmert

I think the text is quite correct, it does say 'may have been employed' for the attack on the Kurds, it does not state 'proof', and there is a reference (in wrong format, but I will help that in a moment). A counterargument may be added with a ref. The second part is also a referenced statement, so I see no problem there. I don't think this is propaganda. It may indeed be that there are not many examples, but you are free to add more. --Dirk Beetstra T C 20:53, 26 August 2006 (UTC)

"Still propaganda in wiki" - wow I may faint.I thought wiki was a propaganda ocean - ref Pellitiere et al - Army War College - as a counter claim - the Iranians used cyanide not the Iraqis. Counterclaim refs on the Zyklon B would be any text book on chemistry or go to the experts on any Holocaust Denial site. The Zyklon B story lacks any technical feasability, much less evidence.— Preceding unsigned comment added by (talkcontribs) 14:47, 6 November 2006‎ (UTC)

Heh heh. "Go to the experts on any Holocaust Denial site". That's a good one. You sly devil. Gzuckier 18:20, 6 November 2006 (UTC)


I added the attempted attack by Aum Shinrikyo in the Tokyo subway with HCN. raptor 14:27, 31 October 2006 (UTC)

Adding to element and compound tables[edit]

You should add critical points and triple points to every element and compound table every articles. Also adding molar volume, and others to every compound table. Chris Dybala 23:25, 5 January 2007 (UTC)

These are values which are rarely used in practical chemistry, which is why they are relegated to the data pages which for compound X, can be found at X (data page). Physchim62 (talk) 15:25, 8 January 2007 (UTC)
I disagree, critical temperatures, pressures and volumes are used daily in Thermodynamics to determine equations of state. Acentric factor should also be included, —The preceding unsigned comment was added by (talk) 19:53, 23 March 2007 (UTC).

Electron on nitrogen[edit]

In the picture of the formula, isnt there should be 2 more unpaired electrons on Nitrogen..cause its not ( H-C:::N: ) —The preceding unsigned comment was added by (talk) 02:58, 14 January 2007 (UTC).

Yes, there is a lone pair on nitrogen, but it is often omitted.
Ben (talk) 04:00, 25 May 2008 (UTC)

No data on synthesis[edit]

It seems, that someone have removed data on how to obtain hydrogen cyanide. -Yyy 09:01, 9 June 2007 (UTC)

Absorption through the skin?[edit]

I heard from my chemistry teacher that hydrocyanic acid can pass through the skin -- he told me about a university lecturer who was lecturing in a practicals lab, and had put his fingers in some nondescript liquid on the desk. After about half an hour he felt ill, and asked the students what they had been doing before he came in. They had been studying the various cyanide complexes - and the liquid was HCN. He went to hospital and survived (luckily).

Should/could the absorption property be mentioned? 01:08, 7 November 2007 (UTC)

It could be mentioned, but better with a reliable source other than hearsay. --Itub 18:05, 8 November 2007 (UTC)

Did Hitler commit suicide with HCN?[edit]

The article claims Hitler committed suicide with HCN; but most writings about this topic state that he used a cyanide capsule, which would be either KCN or NaCN, not HCN. --RisingSunWiki 23:05, 22 May 2008 (UTC)

According to U.K. government information, Hitler used cyanide in capsule form, which would have been a cyanide salt (KCN or NaCN). Based on this information, the article should be modified. --RisingSunWiki 17:16, 24 May 2008 (UTC)

Amount of cyanide to cause death[edit]

Should the amount of cyanide needed to be ingested orally for absolute death necessary for the article? I just figure it could be an interesting fact, seeing as how 100 apple seeds come out to about 10 mg of HCN (I don't want anyone to kill themselves with apple seeds, if you must know). —Preceding unsigned comment added by (talk) 03:01, 15 October 2008 (UTC)

Comments on history[edit]

As a matter of interest, how did they find out it was so poisonous, and how did the discoverer survive?Engineman (talk) 16:24, 8 April 2015 (UTC) There is a problem in the history section, it says "iron oxide plus an a volatile...". I'm not sure if it should be iron oxide plus and a... or iron oxide plus a... or iron oxide and a.... But it should be corrected by someone who does know.

The history section is developing steadily and is interesting, but here are some drive-by critiques:

  • "Hydrogen cyanide was first isolated from a blue dye (Prussian blue)"
probably not really accurate and possibly misleading (implying that Prussian Blue readily gives off HCN easily), the blue dye was probably treated somehow.
  • "which had been accidentally discovered in 1704 in Berlin and widely used as Prussian uniform dye (hence the name), but had a structure which was unknown. It is now known to be a cyanide salt (ferric ferrocyanide). In 1752 the French chemist Pierre Macquer made the important step of showing the Prussian blue could be reduced to a salt of iron, and a new acid which could be used to reconstitute the dye."
that material seems tangential (only vaguely related to HCN, but good maybe for Prussian Blue) and confusing: 'reduced to a salt of iron' means what exactly, are you talking about making ferrocyanide? If the old guys didnt know, there is no utility in propagating their murky notions.
  • Here is the non-tangential and pertinent part of the history section (with minor edits):
"The new acid, Hydrogen cyanide was first isolated from Prussian blue in pure form and characterized about 1783 by the Swedish chemist Carl Wilhelm Scheele. It was eventually given the German name Blausäure (literally "Blue acid") because of its derivation from Prussian blue, and in English became known popularly as Prussic acid. In 1787 the French chemist Claude Louis Berthollet showed that Prussic acid did not contain oxygen, an important contribution to acid theory.[2] In 1815 Joseph Louis Gay-Lussac deduced Prussic acid's chemical formula."

At least that is my take on this section. I didnt want to make changes since I am less expert in the history.--Smokefoot (talk) 21:50, 15 February 2009 (UTC)

Well, I don't agree that saying that something was "isolated" from X means that it happens easily without much treatment. Fluorine was first isolated from fluorospar, and potassium from molten potassium salts by electrolysis, and both of them were considerable undertakings, and use of the word implies nothing about how arduous they were. Since cyanide is locked up in Prussian blue considerably less tightly than the average element is from the compound is was first isolated from, I think the language is perfectly appropriate.

The Macquer work is mentioned in most cyanide histories, because Macquer is the guy who showed that Prussian blue is the combination of a familiar and then well-known iron salt (iron oxide as it turns out) plus a quite unfamiliar acid containing a new radical. That's really the key insight, since before that, nobody knew what Prussian blue was, and even the recipies for making it weren't very good. After Macquer, they were (you just need rust plus this new acid). Compare the various people who worked with lithium minerals-- the key insight was that some of them could be reduced to a previously unknown alkaline earth much like sodium hydroxide, but much lighter. That told them there was a new alkaline element there, ready for isolation, though at the time, nobody had any more ability to do that, than they did to make metallic sodium. But once it was discovered how to make alkali metals by electrolysis, isolating lithium was straightforward work. However, the breakthrough was not that step, at least in my mind, but the realization that you had a new element like sodium, but lighter. Once you know you have a new element, and what salt you have of it is, and what kind of beast it is, getting the stuff is usually straightforward.

Macquer didn't isolate the new acid (and it's probably lucky for him that he didn't try; I'm amazed Scheele survived this and others of his adventures). But Berthollet and Gay-Lussac's work, once they knew what they were after, was fairly straightforward. I think Macquer deserves probably the major credit of the four men in this discovery series, and I didn't want to leave him out for that reason. Macquer's work isn't just vaguely related to HCN-- on the contrary, Macquer is the guy who discovered HCN, if any person can be said to. He just didn't purify it, or figure out its structure. But he DID recognize what he had-- a new acid, and that was the acid this Wiki is about. SBHarris 22:14, 15 February 2009 (UTC)

Thanks for the quick response. You can take or ignore my comments as discardable remarks from an inorganic chemist:

  • "Hydrogen cyanide was first isolated from a blue dye (Prussian blue) which had been accidentally discovered in 1704 in Berlin and widely used as Prussian uniform dye (hence the name), but had a structure which was unknown." the strikeout contains pure digression. Surely you can see this "tangentialness."
  • " an acid then unknown to science,..."
at that time, the very concept of an acid was news and I dont think that there were any compounds for comparison, so this poetic bit is possibly over-dramatic.
  • "...and these could be used to reconstitute the dye. The new acid was hydrogen cyanide."
Now that comment goes to the heart of the history. I will make some small edits but leave the rest to you. Cheers,--Smokefoot (talk) 23:32, 15 February 2009 (UTC)
Agreed. Acids have been known from antiquity, but only the classic strong ones and those you could taste as sour. HCN doesn't qualify and I doubt that Macquer knew he had an acid, though he did know he had something new, and that something is what we now know as HCN. I've tightened up the prose as you suggest. See what you think. SBHarris 23:47, 15 February 2009 (UTC)

Edibility of foods with HCN[edit]

This links in with the post at the top about HCN and foods. Specifically, I'd like to see a note about how HCN isn't exactly fatal in small doses. This site mentions the HCN content of Chokecherry or Prunus virginiana and says that there are claims at health benefits. It doesn't give a source for this, unfortunately, but I think it would be a great thing to add to the page if any sources can be found. Khono (talk) 20:05, 14 July 2009 (UTC)

LD50 value of HCN?[edit]

Why there is no the important LD50 value of HCN which is higly toxic? -- (talk) 17:46, 13 December 2010 (UTC)

Gas chambers[edit]

its interesting that the gas chambers were right next to the ovens. epecially seeing that the gas is highly flammable. — Preceding unsigned comment added by (talk) 14:51, 16 September 2011 (UTC)


It is misleading to state (in section 5) that HCN gas in air is explosive "at concentrations over 5.6%.". This implies that HCN gas is explosive in air at all concentrations over 5.6%, which is incorrect. The Upper Explosive Limit of HCN gas in air is 40%[1].
Is it normal (or a bug) that my link (above) doesn't work when I "Show preview"? Clicking on the link in the preview redirects to this talk page, instead of to the intended external site...
Note that I have just created my wiki account and this is my first post/edit. Sorry if I'm not up with all the rules and etiquette yet. What's the story with using colons? Thanks.
--Carl Barlev (talk) 21:54, 10 February 2012 (UTC)

History of discovery[edit]

as a matter of interest, how is it that no one was apparently killed whilst discovering cyanide? IS there a history of dead scientists / alchemists??— Preceding unsigned comment added by Engineman (talkcontribs) 11:03, 16 June 2012‎ (UTC)

They apparently didn't write a paper on the subject.JSR (talk) 11:51, 16 June 2012 (UTC)


I thought you were done with the citation needed in the name business. These are good names, with the exception of methanenitrile, which is acetonitrile. Zyklon B was a trade name, but, has significant historic interest, as it was the material that contained HCN which was utilized in concentration camp showers in WWII.JSR (talk) 09:39, 16 July 2012 (UTC)

Solubility in water[edit]

The main page lists HCN as miscible in water, yet there's also a wiki answers page (and my chemistry homework) which says that HCN is not soluble in water. Thoughts? — Preceding unsigned comment added by (talk) 20:40, 6 October 2012 (UTC)

Your homework and the wiki answer is wrong. HCN is fully miscible in water (as well as alcohols, ethers, esters, aromatic hydrocarbons, CCl4 and most other organic solvents.). see here. SBHarris 21:08, 6 October 2012 (UTC)

Thanks for the response, I think I've got this sorted out. Feel free to delete unless this may be useful for someone else. — Preceding unsigned comment added by (talk) 02:57, 7 October 2012 (UTC)

Smell (Almonds? Unlikely.)[edit]

The page says "HCN has a faint, bitter, almond-like odor". The smell people associate with almonds is Benzaldehyde, which is released from the glycoside amygdalin in sweet almonds, and along with HCN in bitter almonds. Most people will never have smelled bitter almonds, beause they are not grown commercially (on account of the HCN). It seems extremely unlikely that two chemicals that are utterly different, released from a reaction, should smell the same. It is much more likely that the strong smell of one has led to the impression that the other smells the same. This is especially likely when one is an extremely toxic gas, the smell of which would often indicate that death is imminent.

So, does anyone have any actual evidence (i.e. good researched links) of the true smell of HCN? Fig (talk) 14:28, 6 November 2012 (UTC)

As a chemist I have regularly smelled low concentrations of HCN, since cyanide salts such as NaCN and KCN react with moist air to give off HCN. (KCN + H2O = KOH + HCN). I would describe the odour as almond-like; similar to benzaldehyde, but distinct. Also, I thought amygdalin was a cyanogenic glycoside, which when hydrolysed forms the sugar, plus benzaldehyde cyanohydrin. This latter compound then dissociates into benzaldehyde and HCN. Hence, the almond small from amygdalin would be formed from both compounds. PJJ — Preceding unsigned comment added by (talk) 17:59, 29 December 2012 (UTC)
HCN is relatively concentrated in almonds, if anything, it would be more reminiscent of almonds than anything else. Unless you know of a me concentrated natural source. Plasmic Physics (talk) 20:13, 29 December 2012 (UTC)

Interestingly, Benzonitrile is also listed as smelling of almonds. Fig (talk) 09:55, 9 April 2013 (UTC)

Antidote / Treatment for cyanide poisoning[edit]

How, if at all, can a victim of cyanide poisoning be helped? I feel this question deserves to be discussed in the article, even if the answer is "They can't be". (talk) 01:54, 11 December 2012 (UTC)

Details about treatment are given at cyanide poisoning. Maybe some of that info can be summarized and added here. -- Ed (Edgar181) 12:56, 11 December 2012 (UTC)

used to kill Jews?[edit]

were the Jews the only ones killed in the gas chambers? Or is this just more anti-German propaganda? — Preceding unsigned comment added by (talk) 12:54, 23 April 2013 (UTC)

I removed the comment that implied that Jews were the only victims of hydrogen cyanide. --Smokefoot (talk) 17:05, 23 April 2013 (UTC)

good call. I am personally sick of how the Jews are painted as the only victims. — Preceding unsigned comment added by (talk) 02:38, 24 April 2013 (UTC)

As you can read in the article on Zyklon B, 80% of the victims were jews. Mentioning that jews were the main victims and targets is not anti-German propaganda, it's the only correct deduction from the murderous results of antisemitism. --!nnovativ (talk) 08:39, 12 September 2013 (UTC)

Zyklon B[edit]

Please note that Zyklon B is the name of a pesticide, namely a substrate with HCN as the active species, not just HCN. So, Zyklon B should be removed from the box as "other name". --!nnovativ (talk) 08:35, 12 September 2013 (UTC)

Inorganic vs. Organic[edit]

The statement that HCN is an inorganic compound seems to contradict wikipedia's own definition (and indeed the common definition) of organic molecules, which is that any compound containing carbon and hydrogen are considered organic. I think it would be good to correct this to avoid confusion. — Preceding unsigned comment added by MatthewL16 (talkcontribs) 18:15, 1 November 2013 (UTC)

That is funny. I think HCN should be an inorganic compound (If wikipedia's definition was held as absolute truth, then CO2 and HCO3- should clearly be organic) Nissim 14 (talk) 14:42, 7 October 2015 (UTC)

Cyanide poisoning also from plastics on fire, bitter almonds & the antihypertensive medicine nitroprusside! Antidotes do exist![edit]

Cyanide poisoning may be deadly in minutes. Many people die on fires when they breath cyanide from smoke, especially from plastic materials. Cyanide poisoning may also occur from consumption of bitter almonds and from overdose of the drug nitroprussade! Antidotes for cyanide poisoning do exist and include hydroxocobalamin (a form of vitamin B12!) and also amyl nitrite(administered by inhalation), sodium nitrite, and sodium thiosulfate. 688dim (talk) 23:26, 29 January 2014 (UTC)

Holocaust reminder[edit]

I have added a brief note about the nazi mass murders using the gas, which somehow seem more important than the use of the gas for judicial killing in the USA. Over a million victims I think speaks for itself. I have also added a picture of the Zyklon B canisters from Auschwitz. (talk) 08:46, 28 January 2015 (UTC)

Please stop spamming that image into articles and deleting other images. ChrisGualtieri (talk) 14:30, 28 January 2015 (UTC)