Fosfonat

Fosfonat, often referred to in English as phosphonate, is a class of organophosphorus compounds that contain the phosphonate group. A hallmark feature is a direct phosphorus–carbon bond (P–C) between the phosphorus atom and a carbon substituent, which distinguishes phosphonates from phosphate esters that have P–O–C linkages. The phosphonate group is typically described by a P(V) center bound to one or more OH groups and to carbon-containing substituents, yielding species such as R–P(O)(OH)2.

Phosphonates are generally acidic and can form salts with metals or alkali. Their P–C bond confers notable chemical stability toward hydrolysis, which affects their reactivity and persistence compared with many phosphates. They occur both as synthetic reagents and in naturally produced compounds. Because of this stability and versatility, phosphonates find widespread use across several sectors.

In medicine, phosphonates include the bisphosphonates (for example, alendronate and risedronate), which inhibit bone resorption and are used to treat osteoporosis. The antibiotic fosfomycin contains a phosphonate group and inhibits bacterial cell wall synthesis. In industry and consumer products, phosphonates serve as scale inhibitors and chelating agents in water treatment, detergents, and cleaners due to their ability to bind metal ions. In agriculture, phosphonates appear in fungicides and plant-protection formulations.

Environmental and safety considerations vary by compound; some phosphonates are relatively persistent, while others biodegrade more readily. As with many phosphorus-containing compounds, careful handling and appropriate regulatory guidance apply, especially for pharmaceutical and agricultural uses.