Fosfate

Fosfate, commonly referred to as phosphate in English, designates a class of chemical species derived from phosphoric acid (H3PO4) and containing the phosphate group, PO4^3-, or related esters and anhydrides. In aqueous solutions, phosphate exists in several protonation states, notably orthophosphate (HPO4^2-/H2PO4-) and phosphate (PO4^3-), with pKa values near 2.15, 7.20, and 12.35. Inorganic phosphates include pyrophosphate (P2O7^4-), tripolyphosphate, and longer-chain polyphosphates, which are built from linked phosphate units.

Phosphates occur naturally in minerals such as apatite and are extracted from phosphate rock for fertilizer production. The main industrial route to phosphoric acid is the wet process, where phosphate rock is treated with sulfuric acid to produce phosphoric acid and calcium sulfate. This is followed by reactions to yield various phosphate fertilizers (e.g., monoammonium phosphate, diammonium phosphate, triple superphosphate). Phosphates are also widely used as food additives and in cleaning and water treatment; common food-grade phosphates carry E numbers (e.g., E338–E343).

Biologically, phosphorus is an essential element. Phosphates form the backbone of nucleic acids (DNA, RNA), energy carriers (ATP, ADP), and phospholipids. In organisms, phosphate metabolism includes uptake, storage, and recycling; the phosphorus cycle connects rocks, soils, water, and living systems.

Environmental considerations and safety: Excess phosphate in water bodies can trigger algal blooms and eutrophication. Agricultural practices and wastewater treatment aim to control phosphate discharge. Concentrated phosphoric acid and some phosphate compounds are corrosive; handling and storage guidelines apply. Regulations govern phosphate use in fertilizers and food additives to minimize environmental impact.