Chromate
Chromate and dichromate are strongly oxidizing in acidic conditions, but weakly oxidizing in 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 agents. The oxygen in the air boosts the chromium atom's oxidation state from +3 to +6.