# How can Phosphate be charged at -3? [closed]

I am studying chemistry in High School and I am studying my ions(Because I failed too in the beginning, oops) and I have a question on this reasoning: In Phosphate(PO4), it has a charge of -3. The only way for this to make sense is if half the atoms of oxygen are positive and half are negative bring a positive charge of 4 and negative charge of -3 along with phosphorous being -3. Meaning that there is a total of Negative charge of 7 and positive charge of 4 leaving the total charge of the ion of -3. How come this happens?

• The Wikipedia page about phosphate describes all 4 protonation states of phospahe: 0, -1, -2 and -3, you may want to take a look: en.wikipedia.org/wiki/Phosphate – diogom Feb 14 '18 at 21:45
• Cryptic your words are, young padawan. – Ivan Neretin Feb 14 '18 at 21:58
• Sorry? What if the oxidation state of P was +5 and each oxygen had -2 like we usually expect it? I bet you'd end up with a total charge of -3 on the phosphate as well. – Justanotherchemist Feb 14 '18 at 22:09

All the oxygen atoms have the same oxidation number $-2$. The charge balance then tells that the phosphorous atom has be at a state $+5$. That's the entire story.