Answer : The polyatomic ion with the formula [tex]HPO_4^{2-}[/tex] is called hydrogen phsophate ions.
Explanation :
The rules for naming the ionic compounds with polyatomic ion is given as :
In [tex]HPO_4^{2-}[/tex], hydrogen ion combine with phosphate ion to give hydrogen phosphate ion.
Hence, the polyatomic ion with the formula [tex]HPO_4^{2-}[/tex] is called hydrogen phsophate ions.