Chromate and dichromate

This article is about the salts of the chromium(VI) anion. For other uses, see Chromate. See also for disambiguation of derived terms.
Not to be confused with chromite (compound), monochromat, dichromat, trichromat, or tetrachromat.
Chromate and dichromate
The structure and bonding of the dichromate ion
Ball-and-stick model of the chromate anion
Space-filling model of the dichromate anion
Names
Systematic IUPAC name
Chromate and dichromate
Identifiers
3D model (JSmol)
ChEBI
DrugBank
UNII
  • chromate: InChI=1S/Cr.4O/q;;;2*-1
    Key: ZCDOYSPFYFSLEW-UHFFFAOYSA-N
  • dichromate: InChI=1S/2Cr.7O/q;;;;;;;2*-1
    Key: SOCTUWSJJQCPFX-UHFFFAOYSA-N
  • chromate: [O-][Cr](=O)(=O)[O-]
  • dichromate: O=[Cr](=O)([O-])O[Cr](=O)(=O)[O-]
Properties
CrO2−
4 and Cr
2O2−
7
Molar mass 115.994 g mol−1 and 215.988 g mol−1
Conjugate acid Chromic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chromate salts contain the chromate anion, CrO2−
4. Dichromate salts contain the dichromate anion, Cr
2O2−
7. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.