Interhalogen Compound:

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 :

The action of halogen on low compound of interhalogen. The substance produced depends on the state of the test.
Cl2 F2 → 2CLF;Cl23F2→2ClF3

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,

5BrF53H2OBrO35F6H; lclH2OCLOl2H

 Individual membrane:

1.Chlorine monofluoride, CIF, is formed by direct combination of Cl2 and 200 degrees centigrade F2.
ClF IS  a colourless gas which liquefies to a yellow liquid and solidifies to colourless solid with characteristic odour.
2.Bromine mono-fluoride,BrF  is prepared by reaction of gaseous Br2 with F2at 50 degree Centigrade.
BrF  Is a pale brown gas which liquefies to dark red liquid which freezes to a yellow crystalline solid
3.Iodine monochloride,ICI.
P0tassium iodate and potassium iodide react with HCl to form lCl.
ICI exist as red crystaline solid it is hydrolysed inequas solutin to liberate iodine.
It react with HCl to form a strong acid HICl2
    Isobtained  by direct combination of Iand  Br2
B) AB3 Type
          Chlorine trifluoride ,cIF3 Is prepared by direct combination of cl2 and excess F2 or CIF and excess F2 at 250 c in a nickel tube.
Bromine trifluoride Is prepared by mixing vapour with excess F2 in presence of nitrogen.
BrF3 is good ionizing solvent.
Iodine trichloride Is prepared by the action of excess of chlorine on iodine.
C) AB5 Type.
     Bromine pentafluoride,BrF5 Is obtained by passing by fluorine through BrF3at 90 c.

Iodine pentafluoride Is prepared from iodine and fluorine or form fluorine and heated by iodine pentoxide.

It can be prepared by the action of I2 and AGF.
D) AB7 Type..
Iodine heptafluoride obtained by heating IF5with F2 at 270 t0 300 c.IF5F2IF7

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 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.

Chemical Aspects:

The halogen with lower electronegativity in an interhalogen mixture is in 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.

2BrF5→BrF2BrF4       2IF5→IF4IF6
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