periodate

Periodate is an anion composed of iodine and oxygen. It is one of a number of oxyanions of iodine and is the highest in the series, with iodine existing in oxidation state +7. Unlike other perhalogenates, such as perchlorate, it can exist in two forms: metaperiodate IO− 4 and orthoperiodate IO5− 6. In this regard it is comparable to the tellurate ion from the adjacent period. It can combine with a number of counter ions to form periodates, which may also be regarded as the salts of periodic acid.