PCl5 exists but PH5 does not?

Dhanalakshmi · July 11, 2019, 7:25am

PCl₅ exists but PH₅ does not?

Dhanalakshmi · July 11, 2019, 7:26am

In case of PCl₅ since Chlorine is more electronegative than Phosphorus thus it gets partial positive charge. Thus the orbitals undergo hybridisation.

While in case of PH₅, hydrogen is only very slightly more electronegative than Phosphorus so does not pull significantly on the surrounding electronic charge. Phosphorus pentahydride is a very highly unstable compound and PH5 does not form.