Silver(I) hyponitrite

Silver(I) hyponitrite is an ionic compound with formula Ag2N2O2 or (Ag+
)2[ON=NO]2−, containing monovalent silver cations and hyponitrite anions. It is a bright canary yellow solid practically insoluble in water and most organic solvents, including DMF and DMSO.[1][2][3]

Silver(I) hyponitrite
Names
Other names
Silver hyponitrite, Argentous hyponitrite
Identifiers
3D model (JSmol)
ChemSpider
Properties
Ag2N2O2
Molar mass 275.75
Appearance bright canary yellow solid[1]
Density 5.75 g/cm3 (at 30 °C)
slightly soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Preparation

The compound was described in 1848.[4]

The salt can be precipitated from a solution of sodium hyponitrite in water by the addition of silver nitrate:[2]

Na
2N
2O
2 + 2 AgNO
3 → Ag
2N
2O
2 + 2 NaNO
3

Excess silver nitrate yields a brown or black precipitate.[1][2]

Silver hyponitrite can be prepared also by reducing silver nitrate AgNO
3 with sodium amalgam.[5]

Properties and reactions

Silver hyponitrite is sparingly soluble in concentrated alkali hyponitrite solutions, but quite soluble in aqueous ammonia due to the formation of the complex cation [(NH
3)2Ag]+.[6] The compound is slowly decomposed by light.[5]

The anhydrous compound decomposes in vacuum at 158 °C. The primary decomposition products are silver(I) oxide Ag
2O and nitrous oxide N
2O. However, these then react to form a variable mixture of nitrogen, metallic silver, and various oxides of the two elements and silver salts.[1]

Hyponitrous acid

Reaction of silver hyponitrite with anhydrous hydrogen chloride in ether is the standard way to prepare hyponitrous acid:

Ag
2N
2O
2 + 2 HCl → H
2N
2O
2 + 2 AgCl

Spectroscopic data indicate a trans configuration for the resulting acid.[7]

Alkyl halides

Silver hyponitrite reacts with alkyl halides, to form alkyl hyponitrites. For example, reaction with methyl bromide yields the spontaneously explosive liquid dimethyl hyponitrite:[2]

2 CH
3Br + Ag
2N
2O
2 → H
3C-O-N=N-O-CH
3 + 2 AgBr

Other alkyl hyponitrites reported in the literature include those of ethyl,[8] benzyl,[9][10][11] and tert-butyl.[12][13][14]

References
  1. Trambaklal Mohanlal Oza, Rajnikant Hariprasad Thaker (1955), "The Thermal Decomposition of Silver Hyponitrite". Journal of the American Chemical society, volume 77, issue 19, pages 4976–4980. doi:10.1021/ja01624a007
  2. G. David Mendenhall (1974), "Convenient synthesis of silver hyponitrite". Journal of the American Chemical society, volume 96, issue 15, page 5000. doi:10.1021/ja00822a054
  3. Wiberg, Egon; Holleman, Arnold Frederick (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.
  4. (1848), "On the formation of hyponitrite of silver". Philosophical Magazine Series 3, XIII. Intelligence and miscellaneous articles, volume 33 (1848), issue 219, page 75. doi:10.1080/14786444808646049
  5. Masatsugu Sekiguchi, Michio Kobayashi, Hiroshi Minato (1974), "Reactions between Acyl Halides and Silver Hyponitrite". Bulletin of the Chemical Society of Japan, volume 45, issue 9, pages 2932-2934. doi:10.1246/bcsj.45.2932
  6. C.N. Polydoropoulos, Th. Yannakopoulos (1961), "Silver hyponitrite: Solubility product and complexes in aqueous ammonia". Journal of Inorganic and Nuclear Chemistry, volume 19, issues 1–2, pages 107–114. doi:10.1016/0022-1902(61)80053-5
  7. Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 15: The group 15 elements". Inorganic Chemistry (3rd ed.). Pearson. p. 468. ISBN 978-0-13-175553-6.
  8. J. R. Partington and C. C. Shah (1932), J. Chem. Soc., page 2589.
  9. Ho, S. K.; de Sousa, J. B. (1961). "347. Alkoxy-radicals. Part I. The kinetics of thermal decomposition of dibenzyl hyponitrite in solution". Journal of the Chemical Society (Resumed): 1788. doi:10.1039/JR9610001788.
  10. J. B. Sousa and S. K. Ho (1960), Nature, volume 186, page 776.
  11. Ray, N. H. (1 January 1960). "794. The rates of decomposition of free-radical polymerisation-catalysts: measurements of short half-lives by a thermal method". Journal of the Chemical Society (Resumed): 4023–4028. doi:10.1039/JR9600004023.
  12. H. Kiefer and T. G. Traylor (1966), Tetrahedron Lett., page 6163.
  13. Huang, R. L.; Lee, Tong-Wai; Ong, S. H. (1 January 1969). "Reactions of the α-methoxybenzyl radical in carbon tetrachloride and in other solvents. Carbon tetrachloride as a chlorinating agent". Journal of the Chemical Society C: Organic (1): 40–44. doi:10.1039/J39690000040.
  14. R. C. Neuman and R. J. Bussey (1970), J. Am. Chem. Soc., volume 92, page 2440.
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