What is formed when halogens combine with each other?

Hint: The elements of group \[17\] in the periodic table are named as halogens. The group consists of five main elements which are fluorine, chlorine, bromine and iodine. These elements are highly electronegative in nature due to the presence of seven electrons in its valence subshell. Hence readily attracts an electron to complete its octet.

Complete answer:
When halogens combine or react with each other, they form compounds named as Inter-halogen compounds. Most of the interhalogen compounds are binary i.e., formed by two distinct halogen atoms. There are four types of interhalogen compounds formed which are as follows:
-Diatomic interhalogen compounds (Structural formula \[ = AX\])
-Tetratomic interhalogen compounds (Structural formula \[ = A{X_3}\])
-Hexatonic interhalogen compounds (Structural formula \[ = A{X_5}\])
-Octa-atomic interhalogen compounds (Structural formula \[ = A{X_7}\])
Important properties of Interhalogen compounds:
-The molecules are formed by covalent bonding between the atoms.
-The molecules are diamagnetic in nature.
-The inter-halogen compounds are more reactive than di-halogen compounds because \[A - X\]bond is weaker than \[X - X\] bond.
-The bond length of the compound depends on the size of halogen atoms present.
Applications of Interhalogen compounds:
-These compounds are used as non-aqueous solvents in a chemical reaction.
-These compounds are also used as catalysts in certain reactions.
-These compounds can be used as Fluorinating compounds.
-Some examples of interhalogen compounds are: \[ClF,\,Cl{F_3},\,Br{F_5},\,I{F_7}\], etc.

Note:
Always the halogen atom with bigger size will act as a central atom. Because halogens with bigger size are less electronegative comparatively and hence can donate its electrons to the more electronegative halogen to form chemical bonds.