Berry Pseudorotation
As per classic literature, PF5 shows identical bond lengths of all P-F bonds which are supported by data from NMR and IR spectroscopy which led to the development of berry-pseudo-rotation. But data's from electron diffraction shows that there are eventually two types of bond lengths (P-F (axial)&gt; P-F(equatorial)) which supports the fact that a naive might predict the hybridisation to be sp²d and hence T.B.P. Even in JD lee, it has been clearly stated that this fluctuation may be called the &quot;Paradox&quot; of Chemistry