# What is the name of Pb_3P_2?

Oct 12, 2016

Lead $\left(I I\right)$ phosphide

#### Explanation:

$P b =$lead
$P =$phosphorus$\to$the phosphorus anion is phosphide (${P}^{3 -}$)

• It is important to note that this is phosphide, not phosphate, as the anion does not have oxygen attached
• Phosphate$= P {O}_{4}^{3 -}$

If you are not sure about the oxidation state of lead, add up the oxidation state of the phosphide ${P}^{3 -}$ ions and see what is needed to cancel it out to make it neutral (as this is a compound with a neutral charge).

• Oxidation state of ${P}^{3 -}$ is $- I I I$, since it has gained 3 electrons
• There are 2 ${P}^{3 -}$ in the compound, so $2 \cdot - I I I = - V I$
• To cancel out $- V I$, we need $+ V I$
• There are 3 lead ions, so $\frac{V I}{3} = I I$