Potassium tetraiodomercurate (II)
Structural formula | ||||||||||||||||
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General | ||||||||||||||||
Surname | Potassium tetraiodomercurate (II) | |||||||||||||||
other names |
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Molecular formula | K 2 [HgI 4 ] | |||||||||||||||
Brief description |
light yellow solid |
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properties | ||||||||||||||||
Molar mass | 786.48 g mol −1 | |||||||||||||||
Physical state |
firmly |
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density |
4.29 g cm −3 |
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solubility |
soluble in water |
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safety instructions | ||||||||||||||||
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MAK |
0.02 mg m −3 |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Potassium tetraiodomercurate (II) is a chemical compound from the group of potassium compounds , iodine complexes and mercury compounds .
Extraction and presentation
Potassium tetraiodomercurate (II) can be obtained by reacting mercury (II) chloride or mercury (II) iodide with potassium iodide .
use
Potassium tetraiodomercurate (also known as Neßler's reagent A, after Julius Neßler , who described the solution in his dissertation in 1856) is used in the form of a solution for nitrogen determination. In this Neßler reaction , potassium tetraiodomercurate and ammonia form a red-brown color complex [Hg 2 N] I, the iodide of the cation of Millon's base . The detection is very sensitive to ammonium / ammonia and is used in water analysis for its quantitative determination. The disadvantage is the cross-sensitivity to simple amines , which occur in abundance in strongly revitalized water (e.g. fish ponds, waste water).
The aqueous solution of potassium tetraiodomercurate (from 1 part of mercury (II) iodide and 1.24 parts of potassium iodide with a maximum density of 3.196 g / cm³) is also known as Thoulets solution. The solution, named after the French mineralogist Julien Olivier Thoulet (1843–1936), can be used as a heavy liquid to determine the density of minerals and to separate mineral mixtures.
Individual evidence
- ^ Huey Rong C. Jaw, Margaret M. Mooney, Thomas Novinson, William C. Kaska, Jeffrey I. Zink: Optical properties of the thermochromic compounds disilver tetraiodomercurate (2 -) and dicopper tetraiodomercurate (2–) . In: Inorganic Chemistry . tape 26 , no. 9 , 1987, pp. 1387-1391 , doi : 10.1021 / ic00256a011 .
- ↑ a b c d e Entry on potassium tetraiodomercurate (II) in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
- ↑ Entry on Mayer's reagent. In: Römpp Online . Georg Thieme Verlag, accessed on August 24, 2017.
- ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1506.
- ↑ Julius Neßler: About the behavior of iodine mercury and mercury compounds in general to ammonia and about a new reaction to ammonia . Poppen, Freiburg im Breisgau 1856, urn : nbn: de: bvb: 12-bsb10853243-4 (dissertation, University of Freiburg).
- ↑ Data sheet potassium tetraiodomercurate (II) (PDF) from Merck , accessed on March 2, 2010.
- ↑ Entry on Neßler's reagent. In: Römpp Online . Georg Thieme Verlag, accessed on August 24, 2017.
- ↑ entry to Thoulets solution. In: Römpp Online . Georg Thieme Verlag, accessed on July 23, 2015.