• Chromium(III) oxide (or chromia) is an inorganic compound with the formula Cr2O3. It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite.

  • Because of its considerable stability, chromia is a commonly used pigment. It was originally called viridian. It is used in paints, inks, and glasses.

  • Chromium(III) oxide is a precursor to the magnetic pigment chromium dioxide, by the following reaction:[7] Cr2O3 + 3 CrO3 → 5 CrO2 +  O2

  • It is used as a component of refractories due to its high melting point.

5 Interesting Facts About Chrome Oxide Green:

1. Chrome oxide green was used in ink for dollar bills
Because green chrome oxide was difficult to counterfeit at the end of the Civil War, it was part of the original ink used to print American bills. Today, the Treasury Department uses special inks and other features to increase security

2. Chrome oxide green adds colour to glass products
When manufacturing glass, adding green chrome oxide turns glass a green colour.  Green chrome oxide is used in the production of refractory brick to line metallurgical and glass furnaces/kilns as it has a melting point of 2300°C.

3. Chrome oxide green is a pigment for paints
Green chrome oxide is often used in industrial paints where a lot of wear is involved. For example, military vehicles are painted with green chrome oxide paint. It retains its colour in high heat and light exposure.

4. In paste form, green chrome oxide can be used as an abrasive for blade sharpening
In paste form, chrome oxide green is used an abrasive and can be used to polish glass and sharpen metal blades.

5. Heating ammonium dichromate creates a well known chemical demonstration
When heated, ammonium dichromate decomposes into chromium oxide, nitrogen and water vapor. This video demonstrates a volcano-like (exothermic) well known to chemical faculty: https://edu.rsc.org/exhibition-chemistry/containing-the-dichromate-volcano/3008351.article