Silver(I,III) oxide
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]
 Ag(I) Ag(III) O | |
| Names | |
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| IUPAC name
silver(I,III) Oxide | |
| Other names
tetrasilver tetroxide, silver peroxide, argentic oxide, silver suboxide, divasil | |
| Identifiers | |
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3D model (JSmol) |
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| ECHA InfoCard | 100.013.726 |
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| 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 labelling: | |
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| 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).
Infobox references | |
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
- Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
- David Tudela "Silver(II) Oxide or Silver(I,III) Oxide?" J. Chem. Educ., 2008, volume 85, p 863. doi:10.1021/ed085p863
- Peter Fischer, Martin Jansen "Electrochemical Syntheses of Binary Silver Oxides" 1995, vol. 30, pp. 50–55. doi:10.1002/9780470132616.ch11
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8. p. 1181.
- "FDA Warning Letter to Aidance Skincare and Topical Solutions, LLC | Quackwatch". 19 July 2010.