# What is the oxidation number of phosphorus in the salt Zr_3P_4O_16?

Apr 19, 2017

Well, the parent phosphate ion is $P {O}_{4}^{3 -}$...........
........And so the metal oxidation state would be $\stackrel{+ I V}{M}$.
And thus its perhalide formula would be $M {X}_{4}$, i.e. ${M}^{4 +} + 4 \times {X}^{-}$.
You might get a $\text{zirconium (IV) phosphate}$, you can certainly get $\text{zirconium tetrahalide}$.