Phosphorus can have a total of 4 oxidation states when it forms bonds with oxygen to become an oxyanion (+1, +3, +5, +7). The oxidation state of phosphorus increases by two with each additional oxygen atom in the formula unit. The two oxyanions of phosphorus shown in the table (PO33− and PO43−) correspond to the second lowest and second highest oxidation states of P. Consider the chemical formulas that would correspond to the oxyanions of phosphorus that are missing from the table of common polyatomic ions. What is the chemical formula of the oxyacid hypophosphorous acid?

Express your answer as a chemical formula.