Q.Draw the structure of the chromate ion.

Both chromate (CrO₄²⁻) and dichromate (Cr₂O₇²⁻) are oxoanions of chromium(VI) and moderately strong oxidising agents; chromium is +6 in both. They interconvert in aqueous solution, with chromate predominant in alkaline solution and dichromate predominant in acidic solution.

Chromate is a regular tetrahedron: the central Cr is bonded to four equivalent oxygens, all Cr-O bonds equal at 166 pm, consistent with resonance delocalisation of the -2 charge across all four oxygens. Dichromate is two CrO₄ tetrahedra sharing one corner (bridging) oxygen, linked at a **Cr-O-Cr angl …