From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Chemistry (Rated C-class, High-importance)
WikiProject icon This article is within the scope of WikiProject Chemistry, a collaborative effort to improve the coverage of chemistry on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C-Class article C  This article has been rated as C-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.


I would like to put in a request for information on the definitions of dissolved ammonium, free/exchangeable ammonium and fixed ammonium.

how do we calculate the relative mass formula of ammonium??? someone please help! lyndzi xxx

Explanation for deleting iminium ion[edit]

About a week ago, two mentions of the iminium ion were inserted into this article, effectively stating that an ammonium ion can be called an iminium ion. This is not correct. An iminium ion is the result of putting a positive charge on the nitrogen of an imine. An imine is a compound whose characteristic functional group consists of a nitrogen atom double-bonded to a carbon atom. In order to verify that an iminium ion is not the same as an ammonium ion, I searched for iminium on the web and found the following three references that discuss iminium ions or compounds.

defines iminium cation as an ion with the structure R2C=N+R2, obviously not the same as an ammonium ion.
shows the formation of an iminium ion with the structure R1R2N+=CHR3

shows how an imine is protonated to iminium
R2C=NR ---> R2C=N+HR

I removed both mentions of iminium from the Ammonium article. H Padleckas 10:32, 18 Mar 2005 (UTC)

Double arrow in older image and placement of new pic[edit]

What is wrong with the double arrow in the image? I assume you mean the double arrow in the protonation reaction image. Should the arrows be two single-barbed arrows pointing opposite of each other? If so, I can fix that. A single double-headed arrow would not be correct; that is for resonance structures, not for chemical reactions (such as tautomerism). I suspect the only reason single-barbed arrows were used in the past was laziness to write out the full arrowheads, and it became accepted as a common practice. H Padleckas 16:19, 18 Mar 2005 (UTC)

Yes, I think it should be single-barbed arrows ("⇌" in Unicode-compliant browsers). I cannot remember that I have ever seen a full arrowhead in a scientific publication or book. Cacycle 17:05, 18 Mar 2005 (UTC)
I have uploaded a modified version of the image with single-barbed arrows.
H Padleckas 01:58, 19 Mar 2005 (UTC)

Also, I liked the position of the new "HCl-NH3 fume" pic where I had it placed in the prior edit. In its prior position, this pic was right next to the previously-existing "reacting fumes discussion" in the text. The new position of the pic lets the word "The" float between the two images in an unsightly manner and is no longer next to the discussion. It also crowds the top of the page being together with the other image. H Padleckas 16:19, 18 Mar 2005 (UTC)

That seems to be browser / display-resolution dependent. In Mozilla 1024x768 the photo was sticking to the lower left of the reaction image, leaving a large white text-free space. Cacycle 17:05, 18 Mar 2005 (UTC)

I fixed the "The" problem by placing a non-breaking space after it. H Padleckas 00:48, 12 Jun 2005 (UTC)

List of Ammonium Salts[edit]

I think it was a good idea to move the ammonium salts out of Ammonia. There is more room for them here in Ammonium and I like them here better. H Padleckas 00:52, 12 Jun 2005 (UTC)

Thanks for your support: it was recommended in the worklist of the Chemicals WikiProject, and I just did it. Now we can work on further improving the ammonia article to A-Class. I like your initiatives there and the things that you propose on the talk page there. Wim van Dorst 20:43, 2005 Jun 13 (UTC).
Sorry to spoil the party, but this list doesn't really fit in here either: it should be a link to Category:Ammonium compounds. I shall have to take on my role as Stubmaker-in-general to WP:Chem... In any case, this page needs plenty of work on it:
  • weak acid propeties of ammonium (cringingly bad for the moment)
  • industrial importance of ammonium salts (fertilisers, explosives...)
  • qualitative analysis of ammonium ions (alkali test)
Physchim62 15:49, 21 Jun 2005 (UTC)

Do you mean to make all tiny stubs out of the section? That's a good idea too. And the recommendations for the page are good as well. So much to do and only 24h per day to do them in. Wim van Dorst 20:09, 2005 Jun 21 (UTC).

  • Good idea done. I'll leave the text editorial work on the remaining article to somebody else. Wim van Dorst 20:55, 2005 Jun 21 (UTC).


What is the ΔS for ammonium in J/mol*K?

Structural Formula of Ammonium[edit]

What is the structural formula of ammonium?Patchouli 09:32, 28 March 2006 (UTC)

Acid or metal[edit]

Is ammonium a metal,which is what I was told, or is it a acid,like you say here? —The preceding unsigned comment was added by (talkcontribs) .

It's definitely not a metal, and it's only a very weak acid (you wouldn't usually call it an acid except in the phrases "conjugate acid" of ammonia or "acts as an acid" to a stronger base). —Keenan Pepper 01:23, 21 September 2006 (UTC)

Ammonium amalgam[edit]

Why ammonium amalgam section was deleted? It is a wide-known substance, see [1] for example. Raoul NK 16:26, 3 October 2007 (UTC)

I have reverted my editions, if anybody will delete them, please explain here. Raoul NK 13:53, 12 October 2007 (UTC)

Format & reinstall[edit]

THe symbol NH+
does appear like a NH4 in M$'s Internet Explorer, instead of NH4+. Albmont (talk) 13:05, 11 August 2009 (UTC)

Is ammonium hexachloroplatinate a simple salt[edit]

See title. it says 'most simple salts are very solbule. An exeptio to this ammonium hexachloroplatinate, — Preceding unsigned comment added by GingerGeek (talkcontribs) 14:24, 31 May 2013 (UTC)

Standard Enthalpy of Formation[edit]

According to my textbook the standard enthalpy of formation for NH4+(aq) is -132.5 kJ/mol . Perhaps that's something that should be included. — Preceding unsigned comment added by (talk) 14:42, 23 October 2014 (UTC)

Mostly ammonium ions at pH neutral[edit]

The following line (3rd sentence of the Acid/Base properties section) seems less than accurate "When ammonia is dissolved in water, a tiny amount of it converts to ammonium ions". Actually most of it converts to the ammonium ion. Here's the reasoning - When most people consider water, they are thinking about pH (almost) neutral water (i.e. tap water at pH approx 7). A look at the pKa value (9.25) shows that at pH 9.25, 50% of the ammonia species is ionised. At pH 7 more than 99% of the ammonia is ionised (thus it exists as the ammonium ion). Hence the words "a tiny amount" should be replaced with "most"

Alternatively, an improvement to the 3rd sentence may look something like "When small quantities of ammonia (gas) dissolve in pH neutral water, almost all of the ammonia converts to ammonium ions." BluesLewis (talk) 02:29, 31 December 2016 (UTC)

The flaw in this reasoning is that when ammonia is dissolved in pure water, the pH does not remain equal to 7. If the initial ammonia concentration is 0.1 M (for example), then the equilibrium concentration of [NH4+] and [OH-] is (Kbc)1/2 ≃ (10-5 x 0.1)1/2 = 10-3, so the equilibrium pH is 11 and only a little ammonia becomes NH4+.
A buffered solution would be different. If ammonia is dissolved in a solution maintained at pH 7 by another solute which acts as a buffer, then most of the ammonia becomes NH4+ as you say. Dirac66 (talk) 03:14, 31 December 2016 (UTC)