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Use of the syllable Per
Perhalides V.1.svg
Perhalogen compounds: Perfluoroethane (above) and tetrachlorethylene [tetrachlorethylene, also called “Per” for short] (below).
Peroxides V.1.svg
General structure from top to bottom: organic peroxides, organic hydroperoxides and percarboxylic acids. R is an organyl radical (alkyl radical, aryl radical, arylalkyl radical, etc.). The hydroperoxide with R = H is hydrogen peroxide , the percarboxylic acid with R = H is performic acid.

The prefix Per is used in chemistry to denote organic and inorganic compounds. Per (derived from per = whole) always denotes completeness. Perhydro compounds are fully hydrogenated, in perchloric compounds all hydrogen atoms are replaced by chlorine atoms.

Organic chemistry

Organic compounds which, in addition to carbon, contain the maximum number of atoms of one type of element (usually except for hydrogen) can contain the syllable per in their name , e.g. B. perchlorethane for hexachloroethane or perfluoroethene for tetrafluoroethene . Perchlorethylene (per-, tetrachlorethylene, C 2 Cl 4 ) is also simply called “Per” in chemists' jargon.

Perfluorinated organic compounds are very stable, i.e. substances that are inert. Perfluorinated plastics ( Teflon ) are made from perfluoroalkenes and are of considerable technical importance. Names such as "Perchlor ..." or "Perfluor ..." are permitted according to IUPAC rule C-105.1.

The prefix "Per" is also used in chemistry to denote a molecule that belongs to the compound class of peroxides , hydroperoxides or percarboxylic acids and thus contains the atom group -O-O-. Well-known percarboxylic acids are peracetic acid , perbenzoic acid and m -chloroperbenzoic acid ( MCPBA , from English m -chloro perbenzoic acid).

Decalin - C 10 H 18 - is also called perhydronaphthalene .

Inorganic chemistry

The prefix Per denotes compounds which contain an element in its highest or at least one high oxidation state , e.g. B. perchlorates , permanganates .

Individual evidence

  1. ^ Wolfgang Holland: The nomenclature in organic chemistry , VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1969, page 38.
  2. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , p. 3041.
  3. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , pp. 3045-3046.
  4. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , p. 3042.