Carbon tetraiodide

Tetraiodide

Dark red solid

Fixed

4.32 g · cm -3 ( 20 ° C)

171 ° C ( decomposition)

Reacts with water

Attention

178 mg · kg -1 ( LD50, mouse, i.v.)

392.9 ± 8.2 kJ · mol -1

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Tetraiodmethan (also tetraiodide ) is a chemical compound from the series of Iodkohlenwasserstoffe in which all hydrogen atoms of methane are substituted by iodine atoms. Both terms are correct according to IUPAC nomenclature - depending on whether the connection as organic ( Tetraiodmethan ) or inorganic ( tetraiodide ) compound is considered.

Representation

The synthesis of CI4 is best over the aluminum chloride -catalyzed halogen exchange at room temperature.

The reaction product crystallizes out from the reaction solution. CI4 should be ( 2-8 ° C) stored cool.

Properties

Physical Properties

The bright red Tetraiodmethan together with iodoform the only colored unsaturated organic compound without function.

The weight fraction of the carbon in CI4 is only 2 %. The bond length of carbon-iodine is in the tetrahedrally structured molecule 0.212 ± 0.002 nm, the molecule is packed pronounced with iodine -iodine distances of 0.3459 ± 0.003 nm dense and tight. Very likely, the compound thermally and photochemically unstable for this reason. Hexaiodethan is so far unknown presumably for the same reason, as a molecule.

Tetraiodmethan crystallizes in the tetragonal crystal system in the space group with the lattice parameters a = 641 and c = 956 pm and two formula units per unit cell. Due to the highly symmetric tetrahedral structure of the CI4 - molecules, the compound has no dipole moment.

Chemical Properties

CI4 is almost insoluble in water, reacts with it but slowly with the formation of iodoform and iodine. In organic non-polar solvents, it is readily soluble. Thermally and photochemically decomposes to Tetraiodethen (I2C = CI2 ).

Use

CI4 is used as a reagent for iodination. Alcohols, for example, in a reaction similar to Appel reaction proceeds, are converted to alkyl halides.