Search results
Results from the WOW.Com Content Network
In biological systems, phosphorus can be found as free phosphate anions in solution (inorganic phosphate) or bound to organic molecules as various organophosphates. Inorganic phosphate is generally denoted P i and at physiological (homeostatic) pH primarily consists of a mixture of [HPO 4] 2− and [H 2 PO 4] − ions.
Branched polyphosphoric acids give similarly branched polyphosphate anions. The simplest example of this is triphosphono phosphate [OP(OPO 3) 3] 9− and its partially dissociated versions. The general formula for such (non-cyclic) polyphosphate anions, linear or branched, is [H n+2−k P n O 3n+1] k−, where the charge k may vary from 1 to n + 2.
The most prevalent compounds of phosphorus are derivatives of phosphate (PO 4 3−), a tetrahedral anion. [45] Phosphate is the conjugate base of phosphoric acid, which is produced on a massive scale for use in fertilisers. Being triprotic, phosphoric acid converts stepwise to three conjugate bases:
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Ionic radius, r ion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the cation and anion gives the distance between the ions in a crystal lattice.
They are anions HP(O) 2 OH −. A typical derivative is the salt [NH 4][HP(O) 2 OH]. [7] [6] Many related salts are known, e.g., RbHPHO 3, CsHPHO 3, TlHPHO 3. These salts are prepared by treating phosphorous acid with the metal carbonate. These compounds contain a layer polymeric anion consisting of HPO 3 tetrahedra linked by hydrogen bonds ...
The non-stoichiometric phases have the hydroxyapatite structure with cation vacancies (Ca 2+) and anion (OH −) vacancies. The sites occupied solely by phosphate anions in stoichiometric hydroxyapatite, are occupied by phosphate or hydrogen phosphate, HPO 2− 4, anions. [14]
Removal of all three H + ions gives the phosphate ion PO 3− 4. Removal of one or two protons gives dihydrogen phosphate ion H 2 PO − 4, and the hydrogen phosphate ion HPO 2− 4, respectively. Phosphoric acid forms esters, called organophosphates. [17]