Prefixes and Suffixes in Chemistry

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Prefixes and suffixes are part of the nomenclature of compounds in chemistry . Together with the root name of a connection, they form the name for it. A prefix is the syllable that precedes the parent compound and a suffix is the syllable that follows it.

use

3,5-di bromo -2- chloro -5- ethyl -1- nitro octane
(the four alphabetically sorted prefixes in the name are marked in color)
Propan-2-ol or 2-propanol
Pentanoic acid or butanecarboxylic acid

The nomenclature proceeds as follows: The functional groups and the side chains are named in alphabetical order according to the IUPAC rules , counting syllables such as di-, tri- etc. not counting for the order. The number indicating the position of the functional group is separated by a hyphen and written in front of the prefix and the stem name. There can also be several prefixes in front of a stem name, then they are simply separated by a hyphen, as can be seen in the example of 3,5-dibromo-2-chloro-5-ethyl-1-nitrooctane. The stem name is chosen so that it contains as many functional groups and side chains as possible.

There are functional groups, such as the hydroxy group (-OH), which can be written either as a prefix (hydroxy-) or a suffix (-ol). It usually depends on the other functional groups.

Only one functional group can act as a suffix; if there are more than one functional group, the most senior one is formulated as a suffix. All others are then described by prefixes, this happens in the order mentioned above. In addition, only prefixes and no suffixes are used when naming the substituents on side chains. The position number of the substituent called the suffix can also be placed in front of the suffix, as in propan-2-ol, or directly in front, then it would be called 2-propanol .

Many functional groups have a carbon atom that can either be regarded as part of the parent chain or not. Hence, there are two ways to refer to this functional group as a suffix. For example, if you add the carbon atom of the carboxy group (-COOH) of the main chain of a carboxylic acid , the name is given by the suffix “-acid”. If, however, the carbon atom of the carboxy group is not considered to be part of the parent chain, the designation results from the suffix “- carboxylic acid ”.

Examples

Compound class functional group prefix suffix Example with name
diazonium
salts
Diazonium cation Structural Formula V3.svg -diazonium-
salt
Diazonium cation Structural Formula V4.svg
Benzene diazonium chloride
Ammonium
salts
Ammonium2b.svg -ammonium-
salt
Tetramethylammonium chloride V3b.svg
Tetramethylammonium chloride
Salts of carboxylic acids Carboxylic acid anionV2b.svg -oat Sodium propanoate V3b.svg
Sodium propanoate
Carboxylic acid -COOH Carboxy
-acid -carboxylic acid
CH 3 -COOH
acetic acid

Ethylenecarboxylic acid V3b fett.svg
Ethylene carboxylic acid

Salts of
sulphonic acids
Sulfonic acid anionV1b.svg sulfonate Sodium benzene sulfonateV1b.svg
Sodium benzene sulfonate
Sulfonic acid -SO 3 H Sulfo- sulfonic acid C 6 H 5 SO 3 H
benzenesulfonic acid
Carboxylic acid
esters
–COOR Alkoxycarbonyl -carboxylic
acid-
alkyl esters -alkyl acid esters
CH 3 - COOCH 3 methyl
acetate
Carboxylic acid
halides
–COHal Halocarbonyl -carboxylic acid
halide
-acid halide
CH 3 -COCl acetic acid chloride
carboxylic acid
amides
-CONH 2 Carbamoyl -
carboxamide - acid amide
CH 3 -CH 2 -CONH 2 propanoic acid amide
alkylated
carboxylic acid
amides
–CONHR
(–CONR 2 )
Alkylamino
carbonyl
-carboxylic
acid-
alkylamide -acid alkylamide
CH 3 -CH 2 -CON (CH 3 ) 2 propanoic acid dimethylamide
Nitriles -CN Cyano -carboxylic
acid nitrile- acid nitrile
CH 3 –CH 2 –CN
propanoic acid nitrile (cyanoethane)
aldehyde –CHO Oxo- (formyl-) -al CH 2 O
oxomethane ( formaldehyde )

CH 3 –CHO
ethanal ( acetaldehyde )

Ketones Ketone2Vb fat.svg Oxo- -on Aceton2Vb fett.svg
Propanone ( acetone )
Alcohols -OH Hydroxy -oil CH 3 –CH 2 –OH
ethanol (hydroxyethane)
Phenols -OH Hydroxy C 6 H 5 OH
phenol (hydroxybenzene)
Ether –OR Alkoxy CH 3 –CH 2 –O – CH 3
ethyl methyl ether (methoxyethane)
Peroxides -O-O-R -peroxy- 2-hydroperoxypropane V2b bold.svg
2-hydroperoxypropane
Thio alcohols –SH Mercapto- -thiol CH 3 –CH 2 –SH
ethanethiol (mercaptoethane)
Epoxides
(oxiranes)
Oxiran3b bold.svg Epoxy Epoxypropanv5b bold.svg
Epoxypropane ( methyloxirane )
Amines -NH 2
-NH-R
Amino-
alkylamino-
CH 3 -NH 2
methylamine

CH 3 -CH 2 -NH-CH 3
N -methylaminoethane

Nitro
compounds
-NO 2 Nitro CH 3 -CH 2 -NO 2
nitroethane
Nitroso
compounds
–NO Nitroso C 6 H 5 -NO
nitrosobenzene
Iodine
compounds
–I Iodine CH 3 I
iodomethane
Bromine
compounds
–Br Bromine- CH 2 Br 2
dibromomethane
Chlorine
compounds
-Cl Chlorine- HCCl 3
trichloromethane ( chloroform )
Fluorine
compounds
–F Fluorine- F 2 HC-CHF 2
1,1,2,2-tetrafluoroethane

See also

literature

  • Lothar Döhring, Günther Golisch: Fundamentals of organic chemistry . 4th edition. VEB Deutscher Verlag für Grundstoffindindustrie, Leipzig 1981 , pp. 18-21; Order number : 541 204 1.
  • Adalbert Wollrab: Organic Chemistry. An introduction to teacher training and minor subjects . 3. Edition. Springer Verlag, Berlin Heidelberg 2002 , pp. 43–46; ISBN 978-3-540-43998-1 .