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Phosphoric acids and phosphates

class of chemical species; phosphorus oxyacids and their deprotonated derivatives

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionMar 20, 2026
Entity authorityQ15511048
Source-derived summary

In chemistry, a phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus (P) atom is in the oxidation state +5, and is bonded to four oxygen (O) atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these PO4 tetrahedra may be connected by shared single-bonded oxygens, forming linear or branched chains, cycles, or more complex structures. The single-bonded oxygen atoms that are not shared are completed with acidic hydrogen atoms. The general formula of a phosphoric acid is Hn+2−2xPnO3n+1−x, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure, between 0 and ⁠n + 2/2⁠.

Removal of protons (H+) from k hydroxyl groups –OH leaves anions generically called phosphates (if k = n − 2x + 2) or hydrogen phosphates (if k is between 1 and n − 2x + 1), with general formula [Hn−2x+2−kPnO3n+1−x]k−. The fully dissociated anion (k = n − 2x + 2) has formula [PnO3n−x+1](n−2x+2)−. The term phosphate is also used in organic chemistry for the functional groups that result when one or more of the hydrogens are replaced by bonds to other groups.

These acids, together with their salts and esters, include some of the best-known compounds of phosphorus, of high importance in biochemistry, mineralogy, agriculture, pharmacy, chemical industry, and chemical research.

Acids

Phosphoric acid

The simplest and most commonly encountered of the phosphoric acids is orthophosphoric acid, H3PO4. Indeed, the term phosphoric acid often means this compound specifically (and this is also the current IUPAC nomenclature).

Editorial summary

The public source identifies “Phosphoric acids and phosphates” as class of chemical species; phosphorus oxyacids and their deprotonated derivatives. This brief keeps that definition visible, then builds a research path around Phosphoric, acids and phosphates.

Editorial reviewA practical orientation to terminology and classification, particularly when read beside dated observations, specimens or technical literature. The current 267-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Phosphoric, acids and phosphates providing the first useful test.
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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Mar 20, 2026. The linked authority identifier is Q15511048. None of the 0 selected statements returned an explicit reference.

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This entry incorporates text from Phosphoric acids and phosphates” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.