A periodate is a compound that contains this group. Note that the pronunciation is per-iodate, not period-ate.
See Periodates for a bigger list.
Periodates include two forms. The metaperiodate ion is IO4−; the orthoperiodate ion is IO65−.
Periodate compounds include metaperiodates and orthoperiodates. Usually both are called periodates.
In neutral or weak acid conditions, IO4− is most common, in equilibrium with a smaller amount of H4IO6−. In basic conditions, H3IO62− is formed, plus some other ions.
Like its neighbor, tellurium, and unlike lighter halogens, iodine tends to be hexacoordinate, and the units HnIO6(5−n)- are quite common; but in the case of iodine, tetracoordinate units, such as IO4−, are also quite common.
Sodium metaperiodate can be isolated from the oxidation of sodium iodide with sodium hypochlorite and is best recrystallised from nitric acid. However, electrochemistry offers an easier alternative.
Periodates can cleave carbon-carbon bonds when both carbon atoms bear an oxygen atom, either in the form of a hydroxyl or a carbonyl group. This property is often utilized in molecular biochemistry for the purposes of modifying saccharide rings, as many five- and six-membered sugars often have vicinal diols.