Write down the compound where phosphorus exhibits the lowest oxidation state.

Phosphorus is chemical element number 15 of the Periodic Table of Chemical Elements of DI Mendeleev. It is in the 3rd period of group V of the table of D.I. Mendeleev and exhibits the maximum oxidation state of +5; this chemical element may also exhibit lower positive oxidation states (+1 and +3). The minimum oxidation state of phosphorus is -3, an example of a substance in which phosphorus has this oxidation state is phosphine (PH3). Answer: the minimum oxidation state of the chemical element phosphorus is -3.