How do alkyl, allyl and vinyl halides differ in structure ?

Explanation

The X in an alkyl halide is bonded to `sp^(3)-` hybridized carbon of an alkyl group.

In an allyl halide , there is a C=C bonded to the carbon bearing the X.
`H_(2)C =CHCH_(2) X " ""Allyl halide"`
In vinyl halides X is bonded to an `sp^(2)` -hybridized carbon of an alkene.