Phosphonates are chelating agents used to fight the effects of water hardness. They can bind themselves to metal ions and this way prevent the formation of insoluble precipitates (scale). They are very stable under harsh conditions therefore they are used in a wide variety of industrial applications such as: desalination systems, in low pressure boiler water systems, industrial and municipal cleaning water system, swimming pools, pulp and paper manufacturing, textile manufacturing and detergents among others.
In the detergent industry the work to help diminish the effect of water hardness on the washing process. Furthermore, they also work as a bleach stabilizer in detergents that rely on peroxide bleaching.
In household products, phosphonates are used in powder and liquid detergents, in automatic dishwashing tablets, liquid and powder. Also, in dishwashing soap.