Mercury(II) iodide
-iodide-xtal-3D-SF-A.png) Mercury(II) iodide (α form)
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-iodide-xtal-3D-SF-B.png) Mercury(II) iodide (β form)
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 β (left) and α (right) forms
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| Names | |
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| IUPAC name
Mercury diiodide
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| Other names
Mercuric iodide
Red mercury (α form only) |
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| Identifiers | |
7774-29-0  |
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| ChEBI | CHEBI:49659 |
| ChemSpider | 22893 |
| DrugBank | DB04445 |
| Jmol 3D model | Interactive image |
| PubChem | 24485 |
| UNII | R03O05RB0P |
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| Properties | |
| HgI2 | |
| Molar mass | 454.40 g/mol |
| Appearance | orange-red powder |
| Odor | odorless |
| Density | 6.36 g/cm3 |
| Melting point | 259 °C (498 °F; 532 K) |
| Boiling point | 350 °C (662 °F; 623 K) |
| 0.006 g/100 mL | |
| Solubility | slightly soluble in alcohol, ether, acetone, chloroform, ethyl acetate, CS2, olive oil, castor oil |
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Refractive index (nD)
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2.455 |
| Structure | |
| tetrehedral | |
| Pharmacology | |
| ATC code | D08 |
| Vapor pressure | {{{value}}} |
| Related compounds | |
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Other anions
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Mercury(II) fluoride Mercury(II) chloride Mercury(II) bromide |
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Other cations
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Zinc iodide Cadmium iodide |
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Related compounds
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Mercury(I) iodide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |
Mercury(II) iodide (HgI2) is a chemical compound with an appearance of red-orange crystals. Unlike mercury(II) chloride it is hardly soluble in water (<100 ppm).
Conditions/substances to avoid include: heat, light, bromides, chlorides, ammonia, alkalis, cyanides, copper salts, lead salts, iodoform and hydrogen peroxide.
Contents
Properties
Mercury(II) iodide displays thermochromism; when heated above 126 °C, it undergoes phase transition from the alpha crystalline form to a pale yellow beta form. As the sample cools, it gradually reacquires its original color. It is often used for thermochromism demonstrations.[1]
Production
Mercury(II) iodide is produced by adding an aqueous solution of potassium iodide to an aqueous solution of mercury(II) chloride with stirring; the precipitate is filtered off, washed and dried at 70 °C.
Uses
Mercury(II) iodide is used for preparation of Nessler's reagent, used for detection of presence of ammonia.
Mercury(II) iodide is a semiconductor material, used in some x-ray and gamma ray detection and imaging devices operating at room temperatures.[2]
Mercury(II) iodide can be found extremely rarely in nature as mineral coccinite.
In veterinary medicine, mercury(II) iodide is used in blister ointments in exostoses, bursal enlargement, etc.
It can appear as a precipitate in many reactions.
See also
- Mercury(I) iodide, Hg2I2
References
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<references />, or <references group="..." />- ↑ Thermochromism: Mercury(II) Iodide. Jchemed.chem.wisc.edu. Retrieved on 2011-06-02.
- ↑ Simage, Oy U.S. Patent 6,509,203 Semiconductor imaging device and method for producing same, Issue date: Jan 21, 2003
