[minhduy2110]

sao lại không có HIO4 =.=
H5IO6 cũng chỉ là HIO4.2H2O thôi chứ là cái gì.

Periodic acid,^[1] or iodic(VII) acid^[2] is an oxoacid of iodine having chemical formula HIO₄ or H₅IO₆.
In dilute solution, periodic acid exists as H⁺ and IO₄⁻. When more concentrated, orthoperiodic acid, H₅IO₆, is formed, a rare example of a pentaprotic acid. This can be obtained as a crystalline solid.

~~> wikipedia