What is the formula for phosphorous III oxide?

Answer 1

The formula for phosphorous (III) oxide is determined by the electron shells of the phosphorus and oxygen. Oxygen is in group 6, so it will gain 2 electrons to have a charge of -2 per atom. The Roman numerals (III) with the phosphorous tells us that the phosphorous atoms are in a +3 state, and Roman numerals are used to tell us the ionization state of atoms that have multiple possible states.

The common factor of oxygen's 2 and phosphorous's 3 is 6, so we'll have a +6 charge from the P and a -6 charge form the O. To do that, we'll need 2 P's and 3 O's, so our formula is: P2O3.