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]

Silver(I,III) oxide

Silver(I,III) Oxide   Ag(I)   Ag(III)   O
Names
IUPAC name silver(I,III) Oxide
Other names tetrasilver tetroxide, silver peroxide, argentic oxide, silver suboxide, divasil
Identifiers
CAS Number	1301-96-8 Y 155645-89-9 https://pubchem.ncbi.nlm.nih.gov/compound/44150047 lists only CAS 155645-89-9. Perhaps the CASNo 1301-96-8 is due to https://patents.justia.com/patent/6645531 (Antelman, year 2000): "Tetrasilver tetroxide compositions... have been commercially sold under the poorly named “Ag(II) OXIDE” tradename. They may be obtained from Aldrich Chemical Co., Inc..."
3D model (JSmol)	Interactive image
ECHA InfoCard	100.013.726
EC Number	215-098-2
PubChem CID	44150047
UNII	4C3LTJ9O6J Y
InChI InChI=1S/4Ag.4O Key: RARXNJBGGSMBMG-UHFFFAOYSA-N
SMILES [Ag]O[Ag].O=[Ag]O[Ag]=O
Properties
Chemical formula	Ag4O4 Ag2O.Ag2O3
Molar mass	123.87 g/mol
Appearance	grey-black powder diamagnetic
Density	7.48 g/cm3
Melting point	>100 °C, decomposition
Solubility in water	.0027 g/100 mL
Solubility	soluble in alkalis
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H272, H315, H319, H335
NFPA 704 (fire diamond)	3 0 1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) 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 Ag^IAg^IIIO₂^[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]