# How can I write the formula for sodium phosphide?

Jun 23, 2014

Sodium Phosphide has a formula of $N {a}_{3} P$.

Sodium is a metal cation with a charge of $N {a}^{+ 1}$
Phosphorus is a nonmetal anion with a charge of ${P}^{- 3}$

In order to bond ionically the charges must be equal and opposite.
It will take one -3 phosphide ion to balance three +1 sodium ions forming a magnesium phosphide molecule of $N {a}_{3} P$.

I hope this was helpful.
SMARTERTEACHER