Mercury(II) oxide

  • Mercury
  • Merkurioxid
  • Red precipitate
  • Yellow precipitate
  • Red Leu

Orange - red, odorless solid


11.1 g · cm -3 ( 20 ° C)

> 400 ° C ( decomposition)

0.12 Pa ( 20 ° C)

Practically insoluble in water (0.052 g · l-1 at 25 ° C)


0.1 mg · m-3

18 mg · kg -1 ( LD50, rat, oral)

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Mercury (II ) oxide is a chemical compound selected from the group of the oxides.


In its natural form mercury comes (II ) oxide present as very rare mineral Montroydit.

Production and representation

The form of red mercury ( II) oxide can be obtained by reaction of mercury with oxygen at about 350 ° C or by the pyrolysis of mercury ( II) nitrate, yellow form by precipitation of dissolved Hg2 with alkali. The different color is just the result of different particle sizes, because both forms have the same structure with chains of linear O -Hg -O units and angled (108 ° ) Hg -O -Hg - units.


Mercury (II ) oxide is an orange - red solid, which is poorly soluble in water. As mercury itself is also the oxide very toxic. If you heat mercury, it turns almost black from 400 ° C and then decompose at 500 ° C in oxygen and mercury:


Mercury (II ) oxide can be used for the preparation of pure mercury. Already in 1774 Joseph Priestley discovered that heated mercury releases (II ) oxide, oxygen and mercury, said he did not recognize the resulting gas than oxygen. It is also used as a cathode material for mercury -zinc batteries.



Inhalation at a recording there is a cough. The substance can be absorbed through intact skin. On the skin itself it causes a redness. With oral intake leads to diarrhea and abdominal pain. In principle, the substance is irritating to the respiratory tract, eyes and skin. Repeated or chronic contact with mercury may cause sensitization. It can also lead to the development of renal damage.

Emergency measures

The patient is to save with self-contained breathing from the contaminated environment. Contaminated clothing should be removed and the affected skin is thoroughly rinsed with water. Every patient is given at least four liters of oxygen per minute. In an action on the eye of this is to anesthetize and rinse thoroughly. With oral intake, the patient receives 1 gram of medicinal charcoal per kilogram of body weight. Clinical monitoring must be carried out in any case. In the clinic can be used as a specific antidote dimercaptopropanesulfonic acid.