Fosfiter

Fosfiter, or phosphite, refers to the chemical species derived from phosphorous acid (H3PO3). The term covers the phosphite ion PO3^3− found in salts, as well as organic derivatives known as phosphite esters. Phosphites are distinct from phosphates, which derive from phosphoric acid (H3PO4).

In inorganic form, phosphite occurs as salts of the phosphite ion with metal cations, such as lithium, sodium, or potassium phosphites. These salts are typically colorless solids and can be used as reagents or stabilizers in various chemical processes. Organic phosphites are compounds in which hydrogen atoms on the phosphite are replaced by organic groups; these phosphite esters are commonly used as reducing agents, antioxidants, or stabilizers in manufacturing.

Applications of fosfiter are diverse. In agriculture, phosphite salts are employed as fungicides, particularly against oomycete pathogens such as Phytophthora and Pythium. They can also induce plant defense responses and are used as part of integrated disease management. In industry, phosphite esters act as stabilizers and antioxidants for polymers (for example in plastics and coatings) and as intermediates or reducing agents in organic synthesis. Phosphites may also appear as additives or precursors in various phosphorous-based chemical products.

Safety and handling vary by specific compound. Phosphite materials can be irritants to skin, eyes, and the respiratory system and may pose ecological risks if released untreated into water systems. Proper handling, storage, and disposal in accordance with applicable regulations are advised.

Overall, fosfiter encompasses a family of phosphorus-based compounds used in agriculture, polymer chemistry, and organic synthesis, with properties that depend on whether the substance is a salt or an ester.