Oxidation state +5 Phosphoric acids The phosphoric acids are a class of phosphorus oxoacids where each phosphorus atom bonded to four oxygen atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these tetrahedra may be connected by shared single-bonded oxygens, forming  chains, cycles, or more complex structures. The single-bonded oxygen atoms that are not shared are completed with acidic hydrogen atoms. Their generic formula is Hn−x+2PnO3n−x+1, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure. The smallest compounds of this class with two or more phosphorus atoms are called "oligophosphoric acids", and the larger ones, with open chains , are "polyphosphoric acids"; with no definite separation between the two. Some of the most important members are: Pyrophosphoric acid, (or –O–), with four acid hydrogens. Forms pyrophosphates. Triphosphoric or tripolyphosphoric acid, (or –O––O–), with five acidic hydrogens. Forms triphosphates or tripolyphosphates. Tetraphosphoric acid, (or (–O–)2–O–), with six acidic hydrogens. Forms tetraphosphates. Metaphosphoric, trimetaphosphoric, or    cyclo-triphosphoric acid, (or , (–P(O)(OH)–O–)3), a cyclic molecule with three acidic hydrogens. Forms the metaphosphates  .
Oxidation state +5 The most important members of this group are the phosphoric acids, where each phosphorus atom bonded to four oxygen atoms, one of them through a double bond, arranged as the corners of a tetrahedron. Two or more of these 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. Their generic formula is Hn−x+2PnO3n−x+1, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure. The smallest compounds of this class with two or more phosphorus atoms are called "oligophosphoric acids", and the larger ones, with linear –P–O– backbones , are "polyphosphoric acids"; with no definite separation between the two. Some of the most important members are: Pyrophosphoric acid, (or –O–), with four acid hydrogens. Forms pyrophosphates. Triphosphoric or tripolyphosphoric acid, (or –O––O–), with five acidic hydrogens. Forms triphosphates or tripolyphosphates. Tetraphosphoric acid, (or (–O–)2–O–), with six acidic hydrogens. Forms tetraphosphates. Thebackbone may be branched, as in triphosphono phosphoric acid, or P(O)(–)3, a branched isomer of tetrapolyphosphoric acid. The tetrahedra may be connected to form closed –P–O– chains, as in Trimetaphosphoric, or cyclo-triphosphoric acid, (or , (–P(O)(OH)–O–)3), a cyclic molecule with three acidic hydrogens. Forms the trimetaphosphate salts and esters. Metaphosphoric acid is general term for phosphoric acids with a single cycle, (–P(O)(OH)–O–)n, whose elemental formula is .
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Phosphoric acids The phosphoric acids are a class of phosphorus oxoacids
The most important members of this group are the phosphoric acids,
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linear or branched
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open chains
linear –P–O– backbones
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Metaphosphoric, trimetaphosphoric, or
Thebackbone may be branched, as in
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triphosphono phosphoric acid, or P(O)(–)3, a branched isomer of tetrapolyphosphoric acid.
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The tetrahedra may be connected to form closed –P–O– chains, as in
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Trimetaphosphoric, or
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metaphosphates
trimetaphosphate salts and esters.
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Metaphosphoric acid is general term for phosphoric acids with a single cycle, (–P(O)(OH)–O–)n, whose elemental formula is