hiii

The compounds containing two or more halogen atoms are called inter halogen compounds. Each halogen combines with every other halogen to form interhalogen compounds. For e.g., ClF, ICl₃, BrF₅ etc.

They are of two types:

(i) Neutral molecules containing two or more halogen atoms. For e.g., ICl, BrF

, IF

, IF

etc.

(ii) Negatively charged interhalogen anions or polyhalide ions such as

The different (types of) interhalogens of the type AX (diatomic), AX₃ (tetra atomic), AX₅ (hexa atomic) and AX₇ (octa atomic) are given below:

Some characteristics of inter halogen compounds are:

(i) They are covalent compounds.

(ii) They are more reactive than the constituent halogens. It is because A-X bond is relatively weaker than X-X bond.

(iii) They are very good oxidising agents.

(iv) Their melting and boiling points increase with the increase in the difference of electronegativity.

(v) Chlorofluoro hydrocarbons are known as

and are used as refrigerants. For e.g., Freon-11 is CCl

F, Freon-12 is CCl

F

, Freon-13 is CClF

etc.

Shapes

The molecular structure of interhalogen compounds can be explained on the basis of VSEPR theory. The structures of a few interhalogens are shown in figure.

Structure of interhalogen compounds

It may be noted than in general, the central halogen atom assumes:

a) sp³d hybridization in AX₃ which has a trigonal bipyramidal arrangement.

b) sp

d

hybridization in AX

, which has octahedral arrangement.

c) sp³d³ hybridization in AX₇ which has pentagonal bipyramidal arrangement.

In addition to neutral interhalogen compounds polyhalide ions containing more than two halogen atoms have also been prepared. These are formed by the combination between the halide ion with another halogen atom or with some compound of halogen. For e.g., I

(triodide ion is formed by combination of I

molecule and iodide ion (I

).

             !!!!!!

 yeah but why are they weaker.eg ICl is weaker than Cl2