Silver nitride

Silver nitride is an explosive chemical compound with symbol Ag3N. It is a black, metallic-looking[1] solid which is formed when silver oxide or silver nitrate[2] is dissolved in concentrated solutions of ammonia, causing formation of the diammine silver complex which subsequently breaks down to Ag3N. The standard free energy of the compound is about +315 kJ/mol, making it an endothermic compound which decomposes explosively to metallic silver and nitrogen gas.[3]

Silver nitride
Names
IUPAC name
Silver(I) nitride
Other names
Fulminating silver
Argentous nitride
Identifiers
3D model (JSmol)
ChemSpider
Properties
Ag3N
Molar mass 337.62
Appearance Black solid
Density 9 g/cm3
Boiling point Explodes at 165 °C
Slightly
Solubility Decomposes in acids
Structure
face centered cubic
Hazards
Main hazards Explosive
Safety data sheet
Flash point Flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

History

Silver nitride was formerly referred to as fulminating silver, but this can cause confusion with silver fulminate or silver azide, other compounds which have also been referred to by this name. The fulminate and azide compounds do not form from ammoniacal solutions of Ag2O.[3] Fulminating silver was first prepared in 1788 by the French chemist Claude Louis Berthollet.[4]

Properties

Silver nitride is poorly soluble in water, but decomposes in mineral acids; decomposition is explosive in concentrated acids. It also slowly decomposes in air at room temperature and explodes upon heating to 165 °C.[5]

Hazards

Silver nitride is often produced inadvertently during experiments involving silver compounds and ammonia, leading to surprise detonations. Whether silver nitride is formed depends on the concentration of ammonia in the solution. Silver oxide in 1.52 M ammonia solution readily converts to the nitride, while silver oxide in 0.76 M solution does not form nitride.[3] Silver oxide can also react with dry ammonia to form Ag3N. Silver nitride is more dangerous when dry; dry silver nitride is a contact explosive which may detonate from the slightest touch, even a falling water droplet.[3] It is also explosive when wet, although less so, and explosions do not propagate well in wet deposits of the compound. Because of its long-term instability, undetonated deposits of Ag3N will lose their sensitivity over time.

Silver nitride may appear as black crystals, grains, crusts, or mirrorlike deposits on container walls. Suspected deposits may be dissolved by adding dilute ammonia or concentrated ammonium carbonate solution, removing the explosion hazard.[1][6]

Other uses of the term

The name "silver nitride" is sometimes also used to describe a reflective coating consisting of alternating thin layers of silver metal and silicon nitride. This material is not explosive, and is not a true silver nitride. It is used to coat mirrors and shotguns.[7][8]

See also

References
  1. John L. Ennis and Edward S. Shanley (1991). "On Hazardous Silver Compounds". J. Chem. Educ. 68 (1): A6. Bibcode:1991JChEd..68....6E. doi:10.1021/ed068pA6.
  2. "Silver Nitrate" (PDF). Retrieved February 11, 2010.,
  3. Edward S. Shanley, John L. Ennis (1991). "The Chemistry and Free Energy Formation of Silver Nitride". Ind. Eng. Chem. Res. 30 (11): 2503. doi:10.1021/ie00059a023.
  4. See:
    • Berthollet (1788) "Procéde pour rendre la chaux d'argent fulminante" (Procedure for making fulminating silver chalk), Observations sur la physique … , 32 : 474–475.
    • Davis, Tenney L., The Chemistry of Powder And Explosives (Las Vegas, Nevada: Angriff Press, 1998), p. 401. (Originally published in 1941 and 1943 by Wiley of New York, New York.)
  5. Wolfgang A. Herrmann, Georg Brauer, ed. (2014-05-14). Synthetic methods of organometallic and inorganic chemistry: Volume 5, 1999: Volume 5: Copper, Silver, Gold, Zinc, Cadmium and Mercury. Georg Thieme Verlag. p. 38. ISBN 978-3-13-179211-2.
  6. "Silver oxide". Retrieved February 11, 2010.
  7. "Silicon nitride protective coatings for silvered glass mirrors". Retrieved February 11, 2010.
  8. "Browning Shotguns". Retrieved February 11, 2010.
Salts and covalent derivatives of the nitride ion
NH3
N2H4		 He(N2)11
Li3N Be3N2 BN β-C3N4
g-C3N4
CxNy		 N2 NxOy NF3 Ne
Na3N Mg3N2 AlN Si3N4 PN
P3N5		 SxNy
SN
S4N4		 NCl3 Ar
K Ca3N2 ScN TiN VN CrN
Cr2N		 MnxNy FexNy CoN Ni3N CuN Zn3N2 GaN Ge3N4 As Se NBr3 Kr
Rb Sr3N2 YN ZrN NbN β-Mo2N Tc Ru Rh PdN Ag3N CdN InN Sn Sb Te NI3 Xe
Cs Ba3N2   Hf3N4 TaN WN Re Os Ir Pt Au Hg3N2 TlN Pb BiN Po At Rn
Fr Ra3N2   Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
↓
La CeN Pr Nd Pm Sm Eu GdN Tb Dy Ho Er Tm Yb Lu
Ac Th Pa UN Np Pu Am Cm Bk Cf Es Fm Md No Lr
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