0F2 and ocl2 have 2 BP and 2 LP. it is expected that the bond angle of this molecule should not be ideal and should debite form 109. 5°. the observe result can be explained in terms of π back bonding that is 2 p π and 3D π .this type of bonding occurs in ocl2 because of this presence of the vacant 3D orbital in CL. this is existence of π back bonding increase the cl -o -cl bonding in due to the enhanced BP BP repulsion it may also be noted that due to the engagement of the oxygen lone pair in π back bonding LP LP repulsion also decreases, indirectly help the opening up of the bond angle. In of2 the bond angle will be guided only by the electronegativity rule.