Phosphates are molecules which consist of phosphorus and oxygen. They are essential to all life. There are multiple types of phosphates and they are classified into groups based on the number of phosphorus molecules that they have. These groups are names as follows, orthophosphates, pyrophosphates, tripolyphosphates and polyphosphates. Orthophosphates are phosphate ions containing one phosphorus atom, they have the ion formula PO4-3. Pyrophosphates contain two phosphate atoms and have the ion formula P2O7-4. Tripolyphosphates have three phosphates and have the formula P3O10-5. Polyphosphates have more than three phosphorus atoms and they have the general formula PnO(3n+1)-(n+2).