Meta- (chemistry)

In chemistry, meta is a prefix, used for systematic names in IUPAC nomenclature. It has several meanings.[1]

• 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
    ₂O²⁻
    ₅ + H
    ₂O
  • 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.[2]