Meta (chemistry)

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 (HSO₃⁻) → 1 metabisulfite S₂O₅²⁻ + H₂O and metaphosphoric acid: 3 orthophosphoric acid H₃PO₄ → 1 trimetaphosphoric acid (H₃P₃O₉) + 3 H₂O. Meta-antimonic acid, the dehydrated form of antimonic acid (H₃SbO₄), is HSbO₃.