Which of the following interhalogen compound does not exist?

Reactivity of halogens towards other halogens: Halogens combine amongst themselves to form a number of compounds known as interhalogens of the types XX′, XX'₃, XX'₅ and XX'₇ where X is a larger size halogen and X′ is smaller size halogen.

BrF₂ cannot be formed as it does not lie in the general formula XX', XX'₃, XX'₅ and XX'₇.