PLZ HELP ANYONE THAT CAN PLZ DO SO :) this is 8th grade science btw The compound magnesium phosphate has the chemical formula Mg3(PO4)2. In this compound, phosphorous and oxygen act together as one charged particle, which is connected to magnesium, the other charged particle. What does the 2 mean in the formula 5Mg3(PO4)2? There are two elements in magnesium phosphate. There are two molecules of magnesium phosphate. There are two magnesium ions in a molecule of magnesium phosphate. There are two phosphate ions in a molecule of magnesium phosphate.