fosfathydrogenfosfat

Fosfathydrogenfosfat is the Swedish and some Germanic-language name for hydrogen phosphate, a polyatomic ion derived from phosphoric acid. The most common forms are the dihydrogen phosphate ion, H₂PO₄⁻, and the hydrogen phosphate ion, HPO₄²⁻. These species participate in the proton transfer reactions that govern the buffering capacity of phosphate buffers in aqueous systems. The dihydrogen phosphate ion is the anion that arises when phosphoric acid loses one proton, while the hydrogen phosphate ion results from loss of two protons. Both ions exist in equilibrium in water with the fully protonated phosphoric acid and the fully deprotonated PO₄³⁻, the ratios of which are governed by the pKₐ values of 2.15, 7.20, and 12.35.

In biology, hydrogen phosphate ions play a central role in cellular energy metabolism, acting as the phosphate donor in the hydrolysis of ATP and the synthesis of nucleotides. They also form part of the inorganic phosphate pool in blood plasma and bone mineral, helping to regulate pH and provide structural integrity. Industrially, soluble phosphate salts such as mono- and dibasic sodium phosphate are produced by reacting phosphoric acid with sodium hydroxide or sodium carbonate. These salts are used as food additives, detergents, and water‑softening agents. Safety handling of hydrogen phosphate solutions requires caution, as high concentrations can be corrosive to skin and cause irritation to the eyes and respiratory tract. Proper ventilation and protective equipment are recommended when working with concentrated solutions or in vapor experiments.