In ClF₃ the central chlorine atom is sp³d hybridised and theoretically three structures are possible 

Which of the following is true.

In structure III there are four 90° lp – bp repulsions and no 90° lp – lp repulsions.

In structure I there are 6 lp – bp repulsions at 90°

All the 3 structure are equally stable

Structure III is most stable