The halogen due to the difference in electronegativity , combine with another to form a number of binary compound known as interhalogen compound.
AB, AB3, AB5 and AB7 are classified as four forms of such interhalogen compounds.
Where A and B are two different halogen. The Halogen of lower electronegativity in such a mixture is in a positive oxidation state and the halogen of higher electronegativity is in the oxidation state.
The product formed dependent upon the relative proportion of the two reacting halogens and the temperature. For naming and interhalogen compound is regarded as the halide of the more electropositive halogen. The electro positive iodine trichloride.
Preparation of inter-halogen compound :
Properties of interhalogen compound:
The physical and chemical properties are often intermediate between those of two halogen from which they are derived .They form mixed halide with metals . The interhalogen compound are diamagnetic .
All of them are strong oxidizing agents ,and are all hydrolyzed by water to give the halide ion derived from the smaller halogen atoms and oxo halogen anion derived from the larger halogen. Oxidation state of larger halogen atom does not change during hydrolysis e.g,
A) AB TYPE:
B) AB3 Type
C) AB5 Type.
Iodine pentafluoride Is prepared from iodine and fluorine or form fluorine and heated by iodine pentoxide.
D) AB7 Type..
Inter-halogen compound structure:
The compound of interhalogen al is covalent with the large, less electronegative halogen. As the central atom and the smaller halogen atom as the terminal atoms .The structure of these compound can be understood quite well by the VSEPR model which assumes that their geometry minimize. The repulsion between the binding electrons and the diatomic interhalogen complex of relatively large lone pairs has a linear structure.
The Lewis structure of ClF3 and BrF3 type show a central chlorine and bromine atom bearing three substituent atoms and two lone pair valence electron pairs. Five valance shell electron pair around a central atom lie of a trigonal bipyramid repulsion are minimized in structure of CIF3 and BrF3.
Trigonal bipyramid structure when the lone pair of the central atom lie in the equatorial position .The two lone pair of CI atom in CIF3 and Br atom in BrF3 should occupy equatorial position.
The halogen with lower electronegativity in an interhalogen mixture is in a positive oxidation state.The interhalogen like halogen appears mainly covalent in the vapor phase, but some are recognized in the liquid phase as undergoing self ionization.