Silver sulfate

Silver sulfate

Silver(I) sulfate sample and original bottle.
Names
IUPAC name Silver sulfate
Other names Disilver(1+) sulfate Silver(I) sulfate
Identifiers
Jmol-3D images	Image
SMILES [Ag+].[Ag+].[O-]S([O-])(=O)=O
Properties
Chemical formula	Ag2SO4
Molar mass	311.799 g/mol
Appearance	White solid
Odor	Odorless
Density	5.45 g/cm3 (at 20 °C)
Melting point	652.2–660.0 °C (1,206.0–1,220.0 °F; 925.4–933.1 K)
Boiling point	1,085 °C (1,985 °F; 1,358 K)
Solubility in water	0.57 g/100 mL (0 °C) 0.69 g/100 mL (10 °C) 0.83 g/100 mL (25 °C) 0.96 g/100 mL (40 °C) 1.33 g/100 mL (100 °C)
Solubility	Soluble in conc. sulfuric acid Slightly soluble in acetates, acetone, alcohols, amides, aq. acids, diethyl ether Insoluble in ethanol
Vapor pressure	~0 mmHg
Thermochemistry
Std molar entropy (So298)	200.4 kJ/mol
Std enthalpy of formation (ΔfHo298)	−715.9 kJ/mol
Hazards
Safety data sheet	ScienceLab
Flash point	Non-flammable
Related compounds
Related compounds	Silver nitrate Silver perchlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Silver sulfate is an ionic compound of silver with the formula Ag₂SO₄, mainly used in silver plating and as a non-staining substitute to silver nitrate. It is also used in analytical chemistry.

Properties

Chemical

Silver sulfate darkens upon exposure to light, though this process requires many hours.

Physical

Silver sulfate is a white solid, extremely poorly soluble in water (0.83 g/100 ml at 25 °C), but soluble in concentrated sulfuric acid. It is quite stable under ordinary conditions of use and storage, though it darkens upon exposure to air or light.

Availability

Silver sulfate is sold by various chemical suppliers, though it's not cheap.

Preparation

Silver sulfate can be prepared by reacting concentrated sulfuric acid with silver nitrate:

2 AgNO₃ + H₂SO₄ → Ag₂SO₄ + 2 HNO₃

Hot sulfuric acid will dissolve silver metal, forming silver sulfate:

2 Ag + 2 H₂SO₄ → Ag₂SO₄ + SO₂ + 2 H₂O

Projects

• Silver plating
• Compound collecting

Handling

Safety

Silver sulfate should not be handled without protection, as it will darken when exposed to light.

Storage

Silver sulfate should be kept in closed bottles, away from light and air.

Disposal

Best to recycle it.

References

Relevant Sciencemadness threads

• Silver sulfate
• Sulphur trioxide from silver sulphate
• Silver sulfate