What is Chromate?
{{Ionbox | ImageFile = Chromate-3D-balls.png | ImageSize =160px | ImageAlt = [[Ball-and-stick model]] of the chromate anion | ImageFile2 = Dichromate-3D-balls.png | ImageSize2 =200px | ImageAlt2 = [[Ball-and-stick model]] of the dichromate anion | SystematicName = Chromate and Dichromate | IUPACName = | OtherNames = | Section1 = {{Chembox Identifiers | CASNo = | PubChem = | SMILES = }} | Section2 = {{Chembox Properties | Formula = {{chem|Cr|O|4|2-}} and {{chem|Cr|2|O|7|2-}} | MolarMass = 115.994 g mol<sup>-1</sup> and 215.988 g mol<sup>-1</sup> | Appearance = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | Autoignition = }} }} '''Chromate''' is an [[ion]] that contains one [[chromium]] atom (in its +6 [[oxidation state]]) and four [[oxide]] atoms. Its formula is CrO<sub>4</sub>. Its overall charge is -2. '''Dichromate''' is similar, but it contains two chromium atoms and seven oxide atoms (therefore, Cr<sub>2</sub>O<sub>7</sub>). Chromate and dichromate are strongly [[oxidizing agent|oxidizing]] in [[acid]]ic conditions, but weakly oxidizing in [[base (chemistry)|basic]] conditions. Chromates are generally bright yellow, while dichromates are generally orange or red. They can be made by reaction of [[chromium(III) oxide]] and a metal oxide in a basic environment. They can be destroyed by reaction with [[reducing agent]]s. The [[oxygen]] in the air boosts the chromium atom's oxidation state from +3 to +6. Chromates and dichromates are harmful when powdered because the dust is [[carcinogen]]ic (it can cause [[cancer]]). This can be avoided by [[reduction (chemistry)|reducing]] chromate with something like [[iron(II) sulfate]]. ==Examples== ;Chromates *[[Sodium chromate]] *[[Potassium chromate]] ;Dichromates *[[Potassium dichromate]] *[[Ammonium dichromate]] ==Related pages== *[[Chromium]] *[[Chromium(III) oxide]] {{chem-stub}} [[Category:Chromium compounds]] [[Category:Ions]]