# The PH_3 molecule can be represented in a tetrahedral arrangement similar to NH_3. How does one PH_3 molecule interact with other PH_3 molecules?

Dec 14, 2016

Hydrogen bonding does not operate in phosphine.........

#### Explanation:

For the ammonia molecule, there is a large difference in electronegativity between the hydrogen and nitrogen nuclei, and the nitrogen atom polarizes electron density towards itself, ""^(delta-)N-H^(delta+). The result? Intermolecular hydrogen bonding operates, which is why the boiling point of ammonia, $- 33$ ""^@C, is relatively elevated.

On the other hand, there is not a great of electronegativity difference between the phosphorus atom, and the hydrogen atom. The $P - H$ bond is relatively non-polar as a result.

And the consequence? Because of the reduced intermolecular interaction, the boiling point of phosphine is $- 87.7$ ""^@C. This is even despite the fact that phosphine is a larger molecule than ammonia, with a larger, more polarizable electron cloud.

And thus dispersion forces only operate in phosphine.