The popular reflection at this time is that D orbitals can be used to explain the adhesion of molecules that exceed the octet rule, In this case, the chlorine atom CIF3 is not sp2 hybridized but rather is dsp3 hybridized.
The S, P, and D valence orbitals of the chlorine atom all combine together catalyze 5 hybrid valence orbitals. 2 of these orbitals are "Lone Pair", which bear two electrons each. The other 3 orbitals are bonding orbitals and each contains 1 electron from the chlorine atom and 1 electron from the fluorine atom. A command to use all 7 electrons from the chlorine atom.