2 Replies Latest reply on Aug 9, 2016 8:38 AM by Jon Meredith

    Anhydrous ammonia -> ammonical nitrogen charge?

    Jon Meredith

      Howdy Chemists! Chemistry was not my strong suit in school and so I'm thoroughly out of my realm. I thought I'd ask a question here because I'm hearing two different things from two different people.


      I'm looking at a fertilizer that is ammonical nitrogen that is derived from anhydrous ammonia. Ammonium Nitrate is a neutral charge is my understanding (+ ammonium and - Nitrogen), but I have someone saying that because it's derived from anhydrous ammonia, there is no negative charge to offset the positive - thus leaving it positively charged.


      So is it positively charged or neutral charge? Makes a huge difference for my application.



        • Re: Anhydrous ammonia -> ammonical nitrogen charge?
          Wayne Cook

          Anhydrous ammonia is a gas with no (zero) charge.  It is a very strong base and as such, wants to pick up a hydrogen ion.  When it does, it becomes an ammonium ion and has a plus one (+1) charge.  Ions cannot exist (under normal conditions) without a counter-ion.  Ionic chemical substances must have the same number of positive and negative ions.  This ammonium ion will find a negatively charged ion to give a net neutral charge.  In your example, this ion is a nitrate ion which has a negative one (-1) charge.  One ammonium ion (+1) and one nitrate ion (-1) provides a neutral molecule; ammonium nitrate. 


          If you use anhydrous ammonia (neutral; zero charge) instead of ammonium nitrate, the ammonia gas will react with water to form ammonium hydroxide.  This molecule has an ammonium ion (+1) and a hydroxide ion (-1).  Ammonia is basic enough to ionize water.  This is how ammonium hydroxide (like you can buy at the grocery or hardware stores) is made.  Since ammonium hydroxide is a strong base, it is corrosive to your skin, eyes, lungs, and even some metals (like aluminum). 


          Ammonium nitrate is neutral and not a strong base and is less corrosive.  If you want to fertilize your land, ammonia gas is cheap but hazardous and corrosive.  Ammonium nitrate is a solid and much easier to handle. 


          Check the Safety Data Sheets for ammonium nitrate for the correct safe handling procedures.  These are available from your supplier or on the internet.

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