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 Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

to a persulfate solution e.g. AgNO₃ to a Na₂S₂O₈ solution. It adopts an unusual structure, being a mixed-valence compound. It is a dark brown solid that decomposes with evolution of O₂ in water. It dissolves in concentrated

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

to give brown solutions containing the Ag²⁺ ion.

Structure

Although its empirical formula, AgO, suggests that the compound tetrasilver tetraoxide has silver in the +2

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

, 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 Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted ...

. 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.Wells A.F. (1984) ''Structural Inorganic Chemistry'' 5th edition Oxford Science Publications tetrasilver tetraoxide is therefore formulated as Ag^IAg^IIIO₂ 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 Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold ...

and similar conditions.

References

{{Oxides Silver compounds Mixed valence compounds Transition metal oxides