cobalt ii chromate is an inorganic compound with the chemical formula CoCr2O4. It is a yellowish-brown powder that is soluble in water. It is used as a colorant and dye in ceramics, also as a catalyst for hydrocarbon oxidation. It is a ferromagnetic metal that is useful in making high-strength, superalloys. It is a toxic if inhaled or ingested, and it can cause skin burns if exposed to it for an extended period of time.
To prepare the anhydrous salt, dissolve 4 g of cobalt(II) chloride-6-water in 40 cm 3 of water in a beaker. Stir the solution to keep it mixed. When the solution is completely dissolved, add 2 g of sodium thiosulfate and mix to make a thick paste. This is the anhydrous cobalt(II) chlorate dihydrate.
This anhydrous cobalt(II) chromate is then dried under reduced pressure to form the crystalline solid. Other hydrates of cobalt(II) chromate exist, including the monohydrate (CoCl2