Chemistry:Silver(I,III) oxide

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Silver(I,III) oxide
Silver(I,III) Oxide
Names
IUPAC name
silver(I,III) Oxide
Other names
tetrasilver tetroxide, silver peroxide, argentic oxide, silver suboxide, divasil
Identifiers
3D model (JSmol)
EC Number
  • 215-098-2
UNII
Properties
Ag4O4

Ag2O.Ag2O3

Molar mass 123.87 g/mol
Appearance grey-black powder
diamagnetic
Density 7.48 g/cm3
Melting point >100 °C, decomposition
.0027 g/100 mL
Solubility soluble in alkalis
Hazards
GHS pictograms GHS03: OxidizingGHS05: CorrosiveGHS07: Harmful
GHS Signal word Danger
H272, H315, H319, H335
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

Silver(I,III) oxide or tetrasilver tetroxide is the inorganic compound with the formula Ag4O4. It is a component of silver zinc batteries. It can be prepared by the slow addition of a silver(I) salt to a persulfate solution e.g. AgNO3 to a Na2S2O8 solution.[1] It adopts an unusual structure, being a mixed-valence compound.[2] It is a dark brown solid that decomposes with evolution of O2 in water. It dissolves in concentrated nitric acid to give brown solutions containing the Ag2+ ion.[3]

Structure

Although its empirical formula, AgO, suggests that the compound tetrasilver tetraoxide has silver in the +2 oxidation state, each unit has two monovalent silver atoms bonded to an oxygen atom, and two trivalent silver atoms bonded to three oxygen atoms, and it is in fact diamagnetic. X-ray diffraction studies show that the silver atoms adopt two different coordination environments, one having two collinear oxide neighbours and the other four coplanar oxide neighbours.[1] tetrasilver tetraoxide is therefore formulated as AgIAgIIIO2[4] or Ag2O·Ag2O3. It has previously been called silver peroxide, which is incorrect since it does not contain the peroxide ion, O22−.

Uses

Tetrasilver tetroxide has been marketed under a trade name "Tetrasil." In 2010 The FDA issued a warning letter to an American company concerning the firm's marketing of Tetrasil and Genisil ointments of tetrasilver tetroxide for herpes and similar conditions.[5]

References

  1. 1.0 1.1 Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN:0-19-855370-6
  2. David Tudela "Silver(II) Oxide or Silver(I,III) Oxide?" J. Chem. Educ., 2008, volume 85, p 863. doi: 10.1021/ed085p863
  3. Peter Fischer, Martin Jansen "Electrochemical Syntheses of Binary Silver Oxides" 1995, vol. 30, pp. 50–55. doi:10.1002/9780470132616.ch11
  4. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.  p. 1181.
  5. "FDA Warning Letter to Aidance Skincare and Topical Solutions, LLC | Quackwatch". 19 July 2010. https://quackwatch.org/cases/fdawarning/prod/fda-warning-letters-about-products-2008/aidance/.