Mercuric chloride - HgCl2

What is Mercuric chloride?

HgCl2 is a chemical compound formed by mercury and chlorine with a chemical name Mercuric chloride. It is also called Mercury(II) chloride, or Mercury dichloride, or Dichloromercury. It is highly a toxic compound and is corrosive to mucous membranes.

It is widely used as a disinfectant, antiseptic, fungicide, wood preservative.

Mercury dichloride is odourless crystalline solid white in colour. It is a triatomic molecule where a mercury atom is bonded with two chlorines. It dissolves in water.

Properties of Mercuric chloride – HgCl2

HgCl2

Mercuric chloride

Molecular weight of HgCl2

271.52 g/mol

Density of Mercuric chloride

5.43 g/cm3

Boiling point of Mercuric chloride

304 °C

Melting point of Mercuric chloride

276 °C

Mercuric chloride structure – HgCl2

Structure of Mercuric chloride

The monoisotopic mass and the exact mass of Mercury (II) chloride is 271.908 g/mol. The number of hydrogen bond donors and the number of hydrogen bond acceptors equal to zero. This compound is canonicalized and has one covalently bonded unit only.

HgCl2 Uses (Mercuric chloride)

  • Mercuric chloride is used in the preservation of anatomical specimens.
  • Used in leather tanning.
  • Used in the manufacturing of ink for mercurography.
  • Used as a reagent in analytical chemistry.
  • Used in disinfectant, antiseptic.
  • Used in photography as an intensifier.
  • Used as a catalyst in the conversion of acetylene to vinyl chloride.
  • Its solution is as a dip for bulb and tubers.
  • Used in dry battery cases.
  • Used as an ant repellent.

Production of Mercuric chloride

Mercury (II) chloride is obtained by treating chlorine with mercury (I) chloride or mercury by the and adding hydrochloric acid (HCl) to a hot, concentrated solution of nitrate:

HgNO3 + 2 HCl → HgCl2 + H2O + NO2

Heating a mixture of HgSO4 and sodium chloride (NaCl) gives volatile Mercury (II) chloride, which forms small rhombic crystals. As the temperature increases its solubility increases.

Health hazards:

Mercury dichloride is considered an extremely toxic compound. Any form of mercury is poisonous when absorbed. Probable lethal dosage is 5-50 mg/kg. It is toxic salt of mercury. It attacks the renal systems and gastrointestinal tract.

Learn more about the Structure, physical and chemical properties of HgCl2 from the experts at BYJU’S.

Practise This Question

Cobalt (III) chloride forms several octahedral complexes with ammonia. Which of the following will not give test for chloride ions with silver nitrate at 25?

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