The compound name for hydrogen and phosphorus depends on the ratio of the elements involved. Here are the most common possibilities:

* Phosphine (PH₃): This is the most common compound of hydrogen and phosphorus, and it's a colorless, flammable, and highly toxic gas.

* Diphosphine (P₂H₄): This is a less common compound with a higher ratio of phosphorus to hydrogen. It is also a colorless, flammable, and toxic gas.

The name of the compound will also depend on the oxidation state of phosphorus, but these are the two most common forms.