Sodium carbonate

Sodium carbonate is a white, powdery salt with the formula Na₂CO₃. As soda ash it is one of the most important industrial chemicals, and in its crystal form with water it is washing soda, used for cleaning and softening water.

Its sodium, carbon and oxygen are never combined from the pure elements. Instead it comes two ways. In the United States it is mostly mined as trona, a natural mineral left by ancient lakes in Wyoming, which is dissolved, purified and heated. Most other countries make it by the Solvay process, developed by Ernest Solvay in the 1860s, which turns common salt and limestone into soda ash, with ammonia as a helper that is recycled.

About half of all soda ash goes into glass. In soda-lime glass it is the soda: in the furnace it gives off carbon dioxide and becomes sodium oxide, which breaks up the stiff network of silica so the mix melts at a much lower temperature, saving a lot of fuel. Its other uses include detergents, chemicals and, in the kitchen, ramen noodles, where it helps give the springy texture.