Mercury (I) iodide

Crystal structure
__ Hg +      __ I -
General
Surname	Mercury (I) iodide
Ratio formula	Hg 2 I 2
Brief description	yellow powder
External identifiers / databases
CAS number 15385-57-6 EC number 239-409-6 ECHA InfoCard 100,035,811 PubChem 27243 Wikidata Q60154
properties
Molar mass	654.98 g mol −1
Physical state	firmly
density	7.7 g cm −3
Melting point	140 ° C
boiling point	290 ° C
solubility	almost insoluble in water, ethanol and ether
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 300-310-330-373-410 P: 260-264-273-280-284-301 + 310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Mercury (I) iodide is a chemical compound and belongs to the mercury halides .

Occurrence

Mercury (I) iodide occurs naturally in the form of minerals Moschelit and Iodhydrargyrit before.

Extraction and presentation

Mercury (I) iodide can be represented directly from the elements mercury and iodine :

${\displaystyle \mathrm {2\ Hg+I_{2}\longrightarrow Hg_{2}I_{2}} }$

It is also produced by precipitation from a dilute mercury (I) solution such as mercury (I) nitrate solution with iodide ions . An excess of iodide should be avoided, as the mercury (I) iodide then disproportionates to a 1: 1 mixture of elemental mercury and tetraiodomercurate (II) , which is known as the Nessler reagent .

${\displaystyle \mathrm {Hg_{2}(NO_{3})_{2}+HI\longrightarrow Hg_{2}I_{2}+2\ HNO_{3}} }$

Mercury (I) iodide can also be obtained by reacting mercury with mercury (II) iodide at temperatures below 564 Kelvin or by reacting mercury (II) chloride with tin (II) chloride in an alcoholic solution of potassium iodide .

properties

Mercury (I) iodide is a yellow solid that easily decomposes to mercury and mercury (II) iodide under light . It does not form hydrates and has a tetragonal crystal structure. When heated, it turns orange to red.

use

Mercury (I) iodide was previously used as a drug, but this is no longer the case today due to the high toxicity of the substance.

Individual evidence

1. ↑ ^{a b c} data sheet Mercury (I) iodide from Sigma-Aldrich , accessed on April 22, 2011 ( PDF ).
2. ↑ ^{a b c} Mercury (I) -iodide at webelements.com
3. ↑ Dale L. Perry, Sidney L. Phillips: Handbook of Inorganic Compounds ; ISBN 978-0-84938671-8 .
4. ↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the specified labeling falls under the group entry inorganic compounds of mercury with the exception of mercuric sulphide and those specified elsewhere in this Annex in the Classification and Labeling Inventory of European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
5. ^ Bernard Moody: Comparative Inorganic Chemistry . Elsevier, 2013, ISBN 978-1-4832-8008-0 , pp. 414 ( limited preview in Google Book search).
6. ↑ Erwin Riedel, Christoph Janiak: Inorganic Chemistry . Walter de Gruyter, 2007, ISBN 978-3-11-018903-2 , p. 765 ( limited preview in Google Book search).
7. ^ ^{A b} L. F. Kozin, S. C Hansen: Mercury Handbook Chemistry, Applications and Environmental Impact . Royal Society of Chemistry, 2013, ISBN 978-1-84973-409-7 , pp. 101 ( limited preview in Google Book search).
8. ↑ Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , pp. 256 ( limited preview in Google Book Search).
9. ↑ Mark Weller, Tina Overton, Jonathan Rourke, Fraser Armstrong: Inorganic Chemistry . OUP Oxford, 2014, ISBN 978-0-19-964182-6 , pp. 513 ( limited preview in Google Book search).