| IUPAC name
| Other names
Red mercuric oxide
|Molar mass||216.59 g/mol|
|Appearance||Yellow or red solid|
|Melting point||500 °C (932 °F; 773 K) (decomposes)|
| 0.0053 g/100 ml (25 °C)|
0.0395 g/100 ml (100 °C)
|Solubility|| Reacts with acids|
Insoluble in acetone, alcohols, ammonia, ethers,
|Vapor pressure||~0 mmHg|
Std enthalpy of
|Safety data sheet||Sigma-Aldrich|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
|18 mg/kg (rat, oral)|
| Zinc oxide|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Mercury(II) oxide, or mercuric oxide is a red or orange solid, with the formula HgO.
Mercury(II) oxide reacts with most acids to give mercury salts, making it the basic precursor for any mercury compound.
Mercury(II) oxide is a dense red or orange solid, insoluble in water and organic solvents.
Mercuric oxide can be found in the cathode of old mercury batteries.
Mercury oxide can be bought from chemical suppliers, though it's not easy to get hold of.
Mercury and mercury compounds cannot be freely acquired in EU.
Mercuric oxide can be made via pyrolysis of mercury(II) nitrate at temperature above 360 °C, but below 500 °C.
- Hg(NO3)2 → HgO + 2 NO2 + ½ O2
- HgSO4 + 2 NaOH → HgO + Na2SO4 + H2O
However, the HgO obtained through this route is difficult to purify, as it's difficult to dry and contains lots of unreacted mercuric sulfate.
- Make mercury(II) chloride
- Make elemental mercury
Mercury(II) oxide is extremely toxic. Ingestion may be fatal.
In closed glass or plastic bottles, away from acids.
Mercury(II) oxide should be converted to an insoluble mercury compound, such as mercury sulfide, then taken to hazardous waste disposal centers.