Halogen addition reaction
A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. The general chemical formula of the halogen addition reaction is: C=C + X2 → X−C−C−X (X represents the halogens bromine or chlorine, and in this case, a solvent could be CH2Cl2 or CCl4).
Source: Wikipedia — Halogen addition reaction (CC BY-SA 4.0)