In chemistry, meta is a prefix, used for systematic names in IUPAC nomenclature. It has several meanings.
In organic chemistry, meta indicates the positions of substituents in aromatic cyclic compounds. The substituents have the 1,3-positions, for example in resorcinol.
Meta may also denote the dehydrated form of an acid, salt or organic derivative in a series.
For example metabisulfite:
2 bisulfite (HSO
3−) → 1 metabisulfite S
2O
52− + H
2O
and metaphosphoric acid:
3 orthophosphoric acid H
3PO
4 → 1 trimetaphosphoric acid (H
3P
3O
9) + 3 H
2O.
Meta-antimonic acid, the dehydrated form of antimonic acid (H
3SbO
4), is HSbO
3.