Ammonium amalgam

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Surname

Ammonium amalgam

CAS number

26497-91-6

GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
06 - Toxic or very toxic 08 - Dangerous to health 09 - Dangerous for the environment

danger

H and P phrases H: 330-310-300-373-410
P: ?

Ammonium amalgam is an ammonium-mercury compound. Ammonium salts (NH 4 X ) formed from ammonia (NH 3 ) and acids (HX) are very similar in their properties to the alkali salts (MX), especially the potassium salts. This is due to the similar ionic radii of potassium and ammonium - ion due. Therefore attempts were made at an early stage, similar to the alkali metals , to free an ammonium metal ; however, it was possible to produce the amalgam of the ammonium ion with mercury .

History and representation

The ammonium amalgam was discovered in parallel by Davy and Berzelius in 1808 . It can be represented by electrolysis of ammonium chloride on a mercury cathode as a gray, spongy substance or by reaction of sodium or potassium amalgam with aqueous ammonium salt solutions. In more recent investigations, a structure of the form H 3 N – Hg – H was postulated, which, however, only remains stable for a short time when dissolved in mercury.

properties

Ammonium amalgam is a silvery solid, soft as butter at 20 ° C or a spongy and voluminous mass that decomposes from −30 ° C. At room temperature or on contact with water or alcohols , it sometimes breaks down suddenly into mercury, ammonia and hydrogen :

Individual evidence

  1. ↑ Entry on inorganic mercury compounds in the GESTIS substance database of the IFA , accessed on May 24, 2017 (JavaScript required)
  2. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling falls under the group entry inorganic compounds of mercury with the exception of mercuric sulphide and those specified elsewhere in this Annex in the Classification and Labeling Inventory of European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  3. ^ Prandtl, W .: Humphry Davy, Jöns Jacob Berzelius, two leading chemists from the first half of the 19th century . Scientific publishing company, Stuttgart, 1948
  4. ↑ Hofmann, H., Jander, G .: Qualitative Analysis , 1972, Walter de Gruyter, ISBN 3110036533
  5. ↑ a b Entry on ammonium amalgam. In: Römpp Online . Georg Thieme Verlag, accessed on June 27, 2014.