Metaphosphates

Example: trimetaphosphate

Metaphosphates are condensation products of orthophosphoric acid (H ₃ PO ₄ ) with the empirical formula (M'PO ₃ ) _n . (M ': monovalent cation) In contrast to polyphosphates , metaphosphates combine to form ring molecules . The 6- membered ring of trimetaphosphate is shown as an example . Tetrametaphosphates form an analogous 8-ring.

Trimetaphosphates were previously used in detergents for softening water; Today, because of the fertilizing effect of phosphates and the resulting eutrophication of water, which leads to excessive algae growth, zeolites ( tectosilicates , such as zeolite A ) are used instead.