Silver sulfate

Silver sulfate is the inorganic compound with the formula Ag₂SO₄. It is a white solid with low solubility in water.

Silver sulfate

Skeletal formula of silver sulfate
Sample of silver sulfate
Names
IUPAC name Silver(I) sulfate
Other names Disilver sulfate Argentous sulfate
Identifiers
CAS Number	10294-26-5 Y
3D model (JSmol)	Interactive image
ChemSpider	140554 Y
ECHA InfoCard	100.030.581
EC Number	233-653-7
PubChem CID	159865
UNII	8QG6HV4ZPO Y
UN number	3077
CompTox Dashboard (EPA)	DTXSID70172884
InChI InChI=1S/2Ag.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Y Key: YPNVIBVEFVRZPJ-UHFFFAOYSA-L Y InChI=1/2Ag.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Key: YPNVIBVEFVRZPJ-NUQVWONBAA
SMILES [Ag+].[Ag+].[O-]S([O-])(=O)=O
Properties
Chemical formula	Ag2SO4
Molar mass	311.79 g·mol−1
Appearance	Colorless solid
Odor	Odorless
Density	5.45 g/cm3 (25 °C) 4.84 g/cm3 (660 °C)[1]
Melting point	652.2–660 °C (1,206.0–1,220.0 °F; 925.4–933.1 K)[1][2]
Boiling point	1,085 °C (1,985 °F; 1,358 K)[3][2] decomposition
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)[4]
Solubility product (Ksp)	1.2·10−5[1]
Solubility	Dissolves in aq. acids, alcohols, acetone, ether, acetates, amides[4] Insoluble in ethanol[3]
Solubility in sulfuric acid	8.4498 g/L (0.1 molH2SO4/LH2O)[4] 25.44 g/100 g (13 °C) 31.56 g/100 g (24.5 °C) 127.01 g/100 g (96 °C)[3]
Solubility in ethanol	7.109 g/L (0.5 nEtOH/H2O)[4]
Solubility in acetic acid	7.857 g/L (0.5 nAcOH/H2O)[4]
Magnetic susceptibility (χ)	−9.29·10−5 cm3/mol[1]
Refractive index (nD)	nα = 1.756 nβ = 1.775 nγ = 1.782[5]
Structure
Crystal structure	Orthorhombic, oF56[5]
Space group	Fddd, No. 70[5]
Point group	2/m 2/m 2/m[5]
Lattice constant	a = 10.2699(5) Å, b = 12.7069(7) Å, c = 5.8181(3) Å[5] α = 90°, β = 90°, γ = 90°
Thermochemistry
Heat capacity (C)	131.4 J/mol·K[1]
Std molar entropy (S⦵298)	200.4 J/mol·K [1]
Std enthalpy of formation (ΔfH⦵298)	−715.9 kJ/mol[1]
Gibbs free energy (ΔfG⦵)	−618.4 kJ/mol [1]
Hazards
GHS labelling:
Pictograms	[6]
Signal word	Danger
Hazard statements	H318, H410[6]
Precautionary statements	P273, P280, P305+P351+P338, P501[6]
NFPA 704 (fire diamond)	[2] 2 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

Preparation and structure

Packing of ions in solid silver sulfate. Color code: red = O, yellow = S, gray = Ag.

Silver sulfate precipitates when an aqueous solution of silver nitrate is treated with sulfuric acid:

2 AgNO₃ + H₂SO₄ → Ag₂SO₄ + 2 HNO₃

It is purified by recrystallization from concentrated sulfuric acid, a step that expels traces of nitrate.^[7] Silver sulfate and anhydrous sodium sulfate adopt the same structure.^[8]

Silver(II) sulfate

The synthesis of silver(II) sulfate (AgSO₄) with a divalent silver ion instead of a monovalent silver ion was first reported in 2010^[9] by adding sulfuric acid to silver(II) fluoride (HF escapes). It is a black solid that decomposes exothermically at 120 °C with evolution of oxygen and the formation of the silver(I) pyrosulfate.

AgF₂ + H₂SO₄ → AgSO₄ + 2 HF

4 AgSO₄ → 2 Ag₂S₂O₇ + O₂