In which species does phosphorous have the highest oxidation number?

Phosphorus exhibits its highest oxidation state of +5 in several compounds, most notably in phosphoric acid (H₃PO₄) and its salts (phosphates). This oxidation state is common in various phosphorus-containing species, including phosphoric acid and phosphorus pentachloride (PCl₅). In these compounds, phosphorus forms five bonds, resulting in the maximum oxidation number of +5.