Q. Explain about Dihalide?

Dihalides: Dichlorides and dibromides are formed by the lower members of the group, viz., Se, Te and Po. These are formed mainly by dissociation of the corresponding tetrahalides. Sulphur dichloride can also be formed by chlorination of S₂Cl₂ preferably, in  presence of a trace of a catalyst such as FeCl,. However, due to the decomposition of S₂CI₂, into S₂Cl₂, it is rather unstable. While the dihalides of Se are gaseous, those of Te and Po are solids. These dihalides are hydrolysed by H₂O₂ according to following equation for TeBr₂.

2TeBr₂ + 3H₂O ---------------> H₂TeO₃+ 4HBr + Te

Dissolution of chlorine in sulphur monochloride, S₂Cl₂ gives sulphur dichloride, 9CI₂, an  unstable liquid which dissociates back.