A permanganate is the general name for a chemical compound containing the manganite ion, (MnO−4). Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry. Permanganate solutions are purple in color and are stable in neutral or slightly alkaline media.
Chromate salts contain the chromate anion, CrO2−4. Dichromate salts contain the dichromate anion, Cr2O2−7. They are oxyanions of chromium in the 6+ oxidation state. They are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.
White odorless and tasteless hexagonal or cubic crystal or powder. The relative density is 3.08 (hexagonal) or 2.665 (cubic, 17 ° C). It is hygroscopic. Slightly soluble in water, soluble in hydrochloric acid, solubility slightly increased with increasing temperature. Insoluble in alcohol. Hydrolysis in hot water produces silicic acid.