Periodate

Periodate
	The metaperiodate ion
	The orthoperiodate ion
Names
	Systematic IUPAC name tetraoxoiodate(1−); hexaoxoiodate(5−)
Identifiers
CAS Number	15056-35-6 (metaperiodate) ;
3D model (JSmol)	Metaperiodate: Interactive image; Orthoperiodate: Interactive image;
ChemSpider	146311 (metaperiodate); 5256770 (orthoperiodate);
PubChem CID	167232 (metaperiodate); 6857432 (orthoperiodate);
UNII	B45A1BUM4Q (metaperiodate) ;
	InChI metaperiodate: InChI=1S/HIO4/c2-1(3,4)5/h(H,2,3,4,5)/p-1 Key: KHIWWQKSHDUIBK-UHFFFAOYSA-M; orthoperiodate: InChI=1S/H5IO6/c2-1(3,4,5,6)7/h(H5,2,3,4,5,6,7)/p-5 Key: TWLXDPFBEPBAQB-UHFFFAOYSA-I;
	SMILES Metaperiodate: [O-][I+3]([O-])([O-])[O-]; Orthoperiodate: [O-][I+]([O-])([O-])([O-])([O-])[O-];
Properties
Chemical formula	IO−4 or IO5−6
Conjugate acid	Periodic acid
Related compounds
Other anions	Perchlorate ; Perbromate ; Permanganate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Periodate (/pəˈraɪ.ədeɪt/ pə-RY-ə-dayt) 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 group. 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.