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Mercury(II) chloride

Mercury(II) chloride
Ball-and-stick model of the crystal structure
Space-filling model of the crystal structure
Mercury(II) chloride
Lühuagong(II).JPG
Names
IUPAC names
Mercury(II) chloride
Mercury dichloride
Other names
Mercuric chloride
Corrosive sublimate
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.028.454
EC Number 231-299-8
KEGG
PubChem CID
RTECS number OV9100000
UN number 1624
Properties
HgCl2
Molar mass 271.52 g/mol
Appearance colorless or white solid
Odor odorless
Density 5.43 g/cm3
Melting point 276 °C (529 °F; 549 K)
Boiling point 304 °C (579 °F; 577 K)
3.6 g/100 mL (0 °C)
7.4 g/100 mL (20 °C)
48 g/100 mL (100 °C)
Solubility 4 g/100 mL (ether)
soluble in alcohol, acetone, ethyl acetate
slightly soluble in benzene, CS2, pyridine
Acidity (pKa) 3.2 (0.2M solution)
−82.0·10−6 cm3/mol
1.859
Structure
orthogonal
linear
linear
zero
Thermochemistry
144 J·mol−1·K−1
−230 kJ·mol−1
Pharmacology
D08AK03 (WHO)
Hazards
Safety data sheet ICSC 0979
Very Toxic T+ (T+)
Corrosive C (C)
Dangerous for the Environment (Nature) N (N)
R-phrases R28, R34, R48/24/25, R50/53
S-phrases (S1/2), S36/37/39, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions
Mercury(II) fluoride
Mercury(II) bromide
Mercury(II) iodide
Other cations
Zinc chloride
Cadmium chloride
Mercury(I) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Mercury(II) chloride or mercuric chloride (archaically, corrosive sublimate) is the chemical compound of mercury and chlorine with the formula HgCl2. This white crystalline solid is a laboratory reagent and a molecular compound. Once used as a treatment for syphilis, it is no longer used for medicinal purposes because of mercury toxicity and the availability of superior treatments.

Mercuric chloride exists not as a salt composed of discrete ions, but rather is composed of linear triatomic molecules, hence its tendency to sublime. In the crystal, each mercury atom is bonded to two close chloride ligands with Hg—Cl distance of 2.38 Å; six more chlorides are more distant at 3.38 Å.

Mercuric chloride is obtained by the action of chlorine on mercury or mercury(I) chloride, by the addition of hydrochloric acid to a hot, concentrated solution of mercury(I) compounds such as the nitrate:

Heating a mixture of solid mercury(II) sulfate and sodium chloride also affords volatile HgCl2, which sublimes and condenses in the form of small rhombic crystals.

Its solubility increases from 6% at 20 °C (68 °F) to 36% in 100 °C (212 °F). In the presence of chloride ions, it dissolves to give the tetrahedral coordination complex [HgCl4]2−.

The main application of mercuric chloride is as a catalyst for the conversion of acetylene to vinyl chloride, the precursor to polyvinylchloride:


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