Write a note on halide compounds of group-$16$ elements.

(N/A) The elements of group-$16$ form halides of the type $EX_{6}$,$EX_{4}$,and $EX_{2}$,where $E$ is an element of the group and $X$ is a halogen.
The stability of the halides decreases in the order $F^{-} > Cl^{-} > Br^{-} > I^{-}$. Amongst hexahalides,only hexafluorides are stable. All hexafluorides are gaseous in nature and have an octahedral structure. $SF_{6}$ is exceptionally stable.
Amongst tetrafluorides,$SF_{4}$ is a gas,$SeF_{4}$ is a liquid,and $TeF_{4}$ is a solid. These fluorides exhibit $sp^{3}d$ hybridization and have a trigonal bipyramidal structure,where one of the equatorial positions is occupied by a lone pair of electrons. This geometry is also known as a see-saw geometry.
All elements except oxygen form dichlorides and dibromides. These dihalides are formed by $sp^{3}$ hybridization and have a tetrahedral structure. The well-known monohalides are dimeric in nature.
Examples include $S_{2}F_{2}$,$S_{2}Cl_{2}$,$S_{2}Br_{2}$,$Se_{2}Cl_{2}$,and $Se_{2}Br_{2}$. These dimeric halides undergo disproportionation reactions,for example: $2 Se_{2}Cl_{2} \rightarrow 3 Se + SeCl_{4}$.