Structure, Bonding, General Properties
Almost all organoiodine compounds feature iodide connected to one carbon center. These are usually classified as derivatives of I-. Some organoiodine compounds feature iodine in higher oxidation states.
The C–I bond is the weakest of the carbon–halogen bonds. These bond strengths correlate with the electronegativity of the halogen, decreasing in the order F > Cl > Br > I. This periodic order also follows the atomic radius of halogens and the length of the carbon-halogen bond. For example, in the molecules represented by CH3X, where X is a halide, the carbon-X bonds have strengths, or bond dissociation energies, of 115, 83.7, 72.1, and 57.6 kcal/mol for X = fluoride, chloride, bromide, and iodide, respectively. Of the halides, iodide usually is the best leaving group. Because of the weakness of the C-I bond, samples of organoiodine compounds are often yellow due to an impurity of I2.
A noteworthy aspect of organoiodine compounds is their high density, which arises from the high atomic weight of iodine. For example, one millilitre of methylene iodide weighs 3.325 g.
Read more about this topic: Organoiodine Compound
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