Sodium percarbonate is a chemical, an adduct of sodium carbonate and hydrogen peroxide (a perhydrate), with formula 2Na₂CO₃· 3H₂O₂. It is a colorless, crystalline, hygroscopic and water-soluble solid. It is used in some eco-friendly cleaning products and as a laboratory source of anhydrous hydrogen peroxide.

This product contains the carbonate anion, and should not be confused with sodium peroxocarbonate Na₂CO₄ or peroxodicarbonate Na₂C₂O₆, which contain different anions.

Sodium percarbonate is very neat stuff. It is a powder that releases hydrogen peroxide, and it is very concentrated.

To be complete, sodium percarbonate releases hydrogen peroxide and soda ash. As we know, hydrogen peroxide breaks down into oxygen and water. As you may expect, then, sodium percarbonate breaks down into oxygen, water, and soda ash.

Advantages of using sodium percarbonate

1. It is a granulated powder – which can be nice for scrubbing stains and stuck-on-gunk off of dishes. Think of scouring powder, but made out of hydrogen peroxide. It can be made into a paste, too, and used on tile grout and tough stains.

2. It is easy to carry around -- say, to a laundromat – because of its dry powder form. In fact, laundry products are one of the big applications of sodium percarbonate.

3. It’s cheap. Really cheap: a few dollars for a little tub of it. The recommended amounts are small, it is very concentrated.

4. It is easier to ship than 35% peroxide, since it is not a “hazardous material” for shipping purposes, at least in small quantities. (This is confusing – I’ve seen at least one source that does ship larger quantities, over a couple of pounds, as a hazardous material. I’m not convinced that this is a general practice. I think it is generally shipped as usual, not as a hazardous material. I'm thinking that "pure" sodium percarbonate requires hazardous materials shipping. I'll update this when I know for sure what the distinction is.)

5. It is less likely to splash and spill than liquid peroxide, so it is safer to work with. One does still need to be careful with it, but mostly once it is mixed into water.