What is "periodate"

Periodate \Per*i"o*date\, n. (Chem.) A salt of periodic acid.

n. (context inorganic chemistry English) Either of two oxyanions of iodine; any salt containing these anions

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 and orthoperiodate . 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.

Periodates were discovered by Heinrich Gustav Magnus and C. F. Ammermüller; who first synthesised periodic acid in 1833.