Question

What is the name of `Pb_3P_2`?

Answer 1

Lead `(II)` phosphide

Explanation:

`Pb=`lead
`P=`phosphorus`->`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`=PO_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 `-III`, since it has gained 3 electrons
• There are 2 `P^(3-)` in the compound, so `2*-III=-VI`
• To cancel out `-VI`, we need `+VI`
• There are 3 lead ions, so `(VI)/3=II`