Tetraiodomethane
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| General | ||||||||||||||||
| Surname | Tetraiodomethane | |||||||||||||||
| other names |
Tetraiodocarbon |
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| Molecular formula | CI 4 | |||||||||||||||
| Brief description |
dark red solid |
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| properties | ||||||||||||||||
| Molar mass | 519.63 g mol −1 | |||||||||||||||
| Physical state |
firmly |
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| density |
4.32 g cm −3 (20 ° C) |
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| Melting point |
171 ° C (decomposition) |
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| solubility |
reacts with water |
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| safety instructions | ||||||||||||||||
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| Toxicological data | ||||||||||||||||
| Thermodynamic properties | ||||||||||||||||
| ΔH f 0 |
392.9 ± 8.2 kJ mol −1 |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
Tetraiodide (also tetraiodide ) is a chemical compound from the series of Iodkohlenwasserstoffe in which all hydrogen atoms of methane by iodine atoms substituted are. Both names are according to the IUPAC - Nomenclature correctly - depending on whether the connection as organic ( carbon tetraiodide ) or inorganic ( tetraiodide ) compound is considered.
presentation
The synthesis of CI 4 is best achieved via the aluminum chloride -catalyzed halogen exchange at room temperature.
The reaction product crystallizes out of the reaction solution. CI 4 should be stored in a cool place (2 to 8 ° C).
properties
Physical Properties
The bright red tetraiodomethane, together with iodoform, is the only colored organic compound without an unsaturated function.
The percentage by weight of carbon in CI 4 is only 2%. The bond length carbon-iodine is in the tetrahedral constructed molecule 0.212 ± 0.002 nm . With iodine – iodine distances of 0.3459 ± 0.003 nm, the molecule is extremely dense and tightly packed. For this reason, the compound is very likely to be thermally and photochemically unstable. Hexaiodethane is previously unknown as a molecule, presumably for the same reason.
Tetraiodomethane crystallizes in the tetragonal crystal system in the space group I 4 2 m (space group no. 121) with the lattice parameters a = 641 and c = 956 pm and two formula units per unit cell . Due to the highly symmetrical tetrahedral structure of the CI 4 molecules, the compound has no dipole moment .
Chemical properties
CI 4 is almost insoluble in water, but reacts slowly with it to form iodoform and iodine. It is readily soluble in organic, non-polar solvents. Thermally and photochemically it decomposes to tetraiodethene (I 2 C = CI 2 ).
use
CI 4 is used as a reagent for iodination reactions. For example, alcohols can be converted to alkyl iodides in a reaction similar to the Appel reaction .
Individual evidence
- ↑ a b Datasheet tetraiodomethane from AlfaAesar, accessed on February 11, 2010 ( PDF )(JavaScript required) . .
- ↑ a b entry on tetraiodomethane. In: Römpp Online . Georg Thieme Verlag, accessed on December 25, 2014.
- ↑ a b c Datasheet Tetraiodomethane from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).
- ↑ AS Carson, PG Laye, JB Pedley, Alison M. Welsby: The enthalpies of formation of iodomethane, diiodomethane, triiodomethane, and tetraiodomethane by rotating combustion calorimetry , in: The Journal of Chemical Thermodynamics , 1993 , 25 (2) , p. 261-269; doi : 10.1006 / jcht.1993.1025 .
- ^ RE McArthur, JH Simons: Carbon Tetraiodide , in: Inorganic Syntheses , Vol. III, 1950, pp. 37-39.
- ↑ nastier / nastier: Organic Chemistry , 2nd Edition, Verlag Chemie, Weinheim 1979, pp 404-405..
- ↑ C. Finbak, O. Hassel: Crystal structure and molecular structure of CI 4 and CBr 4 , in: Zeitschrift für Physikalische Chemie , 1937 , 36 , pp. 301-308.
- ↑ S. Pohl: Die Kristallstruktur von CI 4 , in: Zeitschrift für Kristallographie , 1982 , 159 , pp 211-216.
- ^ PR Schreiner, AA Fokin: Carbon Tetraiodide , in: Encyclopedia of Reagents for Organic Synthesis , 2005, John Wiley & Sons, Ltd.
literature
- Harold Soroos, James B. Hinkamp: The Redistribution Reaction. XI. Application to the Preparation of Carbon Tetraiodide and Related Halides , in: J. Am. Chem. Soc. , 1945 , 67 (10) , pp. 1642-1643; doi : 10.1021 / ja01226a004 .
- Naoki Sato, Hiroo Inokuchi: Ionization potentials of carbon tetraiodide and tetraiodoethylene in the solid state , in: Chemical Physics , 1987 , 113 (3) , pp. 445-451; doi : 10.1016 / 0301-0104 (87) 80009-5 .
- H. Stammreich , Yara Tavares and Darwin Bassi: The vibrational spectrum and force constants of carbon tetraiodide , in: Spectrochimica Acta , 1961 , 17 (6) , pp. 661-664; doi : 10.1016 / 0371-1951 (61) 80127-6 .
- K. Sathianandan, K. Ramaswamy and Forrest F. Cleveland: Substituted methanes Part XXXI. Molecular constants of carbon tetraiodide from vibrational spectra , in: Journal of Molecular Spectroscopy , 1962 , 8 (1-6) , pp. 470-474; doi : 10.1016 / 0022-2852 (62) 90045-0 .
- Teresa Roldán-Arjona, Carmen Pueyo: Mutagenic and lethal effects of halogenated methanes in the Ara test of Salmonella typhimurium: quantitative relationship with chemical reactivity , in: Mutagenesis , 1993 , 8 , pp. 127-131; Abstract .
- A. Anderson: Raman and infrared spectra of some tetrahalide crystals , in: Journal of Molecular Structure , 1986 , 143 , pp. 95-100; doi : 10.1016 / 0022-2860 (86) 85213-9 .
