M2PO4

M2PO4 is a general chemical formula representing a compound containing two cations, represented by "M", and a phosphate anion, PO4. The cation "M" can be any monovalent metal ion, such as sodium (Na+), potassium (K+), or lithium (Li+). The specific properties of M2PO4 compounds depend on the identity of the metal ion. For example, disodium phosphate (Na2HPO4) is commonly used as a food additive and buffering agent. Dipotassium phosphate (K2HPO4) also finds applications in food processing and as a fertilizer. Dilithium phosphate (Li2HPO4) is less common but may have specialized uses.

The phosphate group (PO4) is a polyatomic anion with a charge of -3. In M2PO4, the two monovalent cations (each with a charge of +1) balance the charge of the phosphate anion, resulting in a neutral compound. These compounds are typically ionic solids. Their solubility in water varies depending on the specific metal cation. For instance, sodium and potassium phosphates are generally soluble, while phosphates of heavier alkali metals or alkaline earth metals are less so. The chemical behavior of M2PO4 compounds is largely dictated by the properties of the phosphate anion, which can participate in various chemical reactions, including acid-base reactions and precipitation.