From: nreitzel@lonestar.utsa.edu (Norman L. Reitzel   )
Newsgroups: rec.pyrotechnics
Subject: Re: Siver fulminate vs fulminate of silver
Date: 29 Oct 1994 11:04:13 GMT
Message-ID: <38ta7d$im2@ringer.cs.utsa.edu>

In article <1994Oct29.034124.4130@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:

>: and has no use other than as a lab curiousity.  Davis states that
>: [in his day] it had defied analysis because it was so unstable

>: but I am unaware of its true formula.  Anyone out there know?

> There have been a number of formulas ascribed to the substance. I have
> seen AgNH2 and AG2NH (amides), AgO.NH3 (note that this is similar to
> the NI3.NH3 ammonia/iodine complex, Ag3N2 and Ag3N (nitrides). Baum
> states that the formula is Ag2O.NH3.

After reading a bunch of conflicting references, I decided to try it and
see.  I used a TFE tube with AgNO3 dissolved in NaOH/NH4OH.  After 48
hours, there was black stuff in the bottom of the tube.  I froze the tube
in liquid N2 and removed the aqueous bolus with the black stuff on the
end, and used a cooled knife to remove about 8mg of the black powder to a
cuvette (also containing liquid N2).  The remaining ice cube was
destroyed in dilute nitric acid.

The cuvette was evacuated at ~4 Torr (decided not to use my expensive
pump!) and left to evaporate overnight.  Next morning, there was 6.8 mg
of black powder in the bottom.  I sealed the cuvette and refroze it in
liquid nitrogen, then ran an X-ray diffraction (powder) on the sample.

Results were in line with the literature.  I found AgNH2.NH3, in a
hexagonal lattice, bar3 2/m.  Cell parameters: a = 4.60, c=14.2, Z=2
Apparently the NH3 units occupy the tetrahedral sites, with the NH2 units
in a calcite-structure cell.  There was also evidence of free Ag and
Ag2O, indicating that the substance was not very uniform.

I attempted to get optical information on the substance, but when I
placed the cover glass on the slide the compound detonated (at LN2
temperatures!) shattering the slide and the cover glass, and eliciting a
rather surprized explitive from this researcher.

I know why nobody messes with this gunk.  I was -convinced- it would be
stable at 77K, and I took great pains to keep it cold.  Ah well.  Details
available by snail mail, for anyone that wants 'em.

  ------------------------------------------------------------------------
  Norman L. Reitzel, Jr.       |    "When you live beside the graveyard,
  nreitzel@lonestar.utsa.edu   |     you can't cry for every funeral."
  Blue Water Ventures, dba.    |                     Russian Proverb
  ------------------------------------------------------------------------