Mercury(II) sulfate

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Mercury(II) sulfate bottle sample.jpg
Mercury(II) sulfate sample and original bottle.
IUPAC name
Mercury(II) sulfate
Other names
Mercuric sulfate
Mercury persulfate
Mercury bisulfate
Molar mass 296.653 g/mol
Appearance White crystalline powder
Odor Odorless
Density 6.47 g/cm3
Melting point 450 °C (842 °F; 723 K) (decomposes)
Boiling point Sublimes; decomposes
Decomposes to sulfuric acid and HgSO4·2HgO
Solubility Soluble in conc. hydrochloric acid, nitric acid, dil. sulfuric acid, aq. NaCl solution
Insoluble in acetone, ammonia, ethanol, halocarbons, hydrocarbons
Vapor pressure ~0 mmHg
−707.5 kJ/mol
Safety data sheet Fischer Scientific
Flash point Non-flammable
Related compounds
Related compounds
Zinc sulfate
Cadmium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Mercury(II) sulfate or mercuric sulfate, is the chemical compound HgSO4, a toxic and corrosive compound of mercury, used in various chemical reactions, though mostly used in analytical chemistry.



Mercury(II) sulfate readily hydrolyzes in water, separating into the yellow mercuric subsulfate and sulfuric acid:

3 HgSO4 + 2 H2O → HgSO4·2HgO + 2 H2SO4

Heating mercury(II) sulfate above 450 °C will cause it to decompose, releasing hazardous mercury vapors:

HgSO4 → Hg + SO2 + O2


Mercury(II) sulfate is a dense white solid, soluble in concentrated mineral acids, such as nitric acid, sulfuric acid, but insoluble in organic solvents. It hydrolyzes in contact with water, forming yellow mercuric subsulfate and sulfuric acid. Mercury sulfate decomposes when heated to 450 °C. Its density at standard conditions is 6.47 g/cm3.


Mercury(II) sulfate is sold by chemical suppliers. Due to its hazards, this compound is extremely difficult to acquire by the amateur chemist. In the EU, purchasing mercury compounds requires a hazard permit.


Mercury(II) sulfate can be prepared by reacting hot concentrated sulfuric acid with elemental mercury:

Hg + 2 H2SO4 → HgSO4 + SO2 + 2 H2O

It can also be made by reacting mercuric oxide with concentrated sulfuric acid.

HgO + H2SO4 → HgSO4 + H2O

Concentrated acid needs to be used, to prevent hydrolysis.


  • Detect tertiary alcohols
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HgSO4 is extremely toxic and its ingestion may be fatal. Exposure to mercury compounds will cause severe neurological damage. Reaction with water releases sulfuric acid, which is corrosive. The salt itself or as a solution is corrosive to many metals, such as aluminium, copper, iron (most steels), lead, magnesium, zinc, etc.


Mercury(II) sulfate should be stored in closed bottles, away from moisture, in a special cabinet for hazardous substances.


Best to take it to hazardous waste disposal centers.


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