Naming polyatomic anions can be quite confusing due to being seemingly random however there are consistent rules to be followed. 

For example, the prefix 'bi' is used to indicate an extra positive hydrogen which can be shown by the difference between  between carbonate and bicarbonate.

Another example is the suffices "ite" and "ate," which is based on number of oxygen atoms where "ite" means one less O than "ate", this difference is present when comparing sulfite and sulfate.

According to the information above infer the formula of biphosphate