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R-0.1.3 Punctuation

Punctuation in chemical names is frequently of great importance, especially to avoid ambiguity.

R- Commas are used to separate locants that refer to the same part of a name, i.e., locants of a series, and to separate letters or letter combinations that denote fusion sites in names of fused ring systems.

Examples to R-

1,2-Dichloroethane (R-5.3.1)

Dibenzo[a,j]anthracene (R-2.4.1)

N,N-Diethyl-2-furamide (R-

R- Full stops (periods) separate numerical ring size indicator in names constructed according to the von Baeyer system and in certain spiro names.

Examples to R-

Bicyclo[3.2.1]octane (R-2.4.2)

6-Oxaspiro[4.5]decane (R-2.4.3)

R- Colons separate related sets of locants; if a higher level of separation is required, semicolons are employed.

Examples to R-





1,1':2',1"-Tercyclopropane (R-2.4.4)

R- Hyphensseparate:

(a) locants from the words or syllables of a name;

(b) adjacent locants referring to different parts of the name (but preferably parentheses should be inserted);

(c) the two parts of the designation for a primary fusion site in a name for a fused ring system;

(d) a stereodescriptor and the name.

Examples to R-

N-Acetyl-N-(2-naphthyl)benzamide (R-

(preferred to N-Acetyl-N-2-naphthylbenzamide)

2-(3-Pyridyloxy)pyrazine (R-5.5.4)

Thieno[3,2-b]furan (R-

(E)-But-2-ene (R-7.1.2)

After parentheses, a hyphen only appears if the final parenthesis is followed by a locant, for example, 3-(bromocarbonyl)-4-(chlorocarbonyl)-2-methylbenzoic acid. Long hyphens are used in certain names (see R-

R- Spaces are a very important type of punctuation for many kinds of names in the English language. If a space is required in a name, it must be used for the name to be unambiguous. On the other hand, the use of spaces where they are not required may be misleading. Spaces are used in names as follows and are not used in any other names.

R- Spaces separate words in most functional class names, the class name being expressed as one word and the remainder of the molecule as one (or more) separate words. Many compounds may be described by such names, such as:

(a) acids and their derivatives, such as salts, esters and anhydrides;

Examples to R-

Acetic acid (R-9.1, Table 28(a))

Potassium sodium succinate (R-

Ethyl acetate (R-

Phthalic anhydride (R-

(b) carbonyl compounds and their derivatives, such as ketones, acetals, hydrazones, and oximes;

Examples to R-

Ethyl methyl ketone (R-

Cyclohexanone ethyl methyl ketal (R-

Benzaldehyde oxime (R-

(c) halogen and pseudohalogen compounds;

Examples to R-

tert-Butyl chloride (R-5.3.1)

Methyl cyanide (R-

Acetyl chloride (R-5.7.6)

(d) oxygen compounds (alcohols, ethers, peroxides, etc.) and their chalcogen analogues;

Examples to R-

Ethyl alcohol (R-

Ethyl vinyl ether (R-5.5.4)

Ethyl phenyl peroxide (R-5.5.5)

Methyl propyl sulfide (R-5.5.4)

Butyl methyl sulfoxide (R-5.5.7)

R- Spaces separate words in additive names.

Examples to R-

Styrene oxide (R-

Trimethylarsane sulfide (R-

R-0.1.4 Numerical (multiplicative) prefixes
R-0.1.5 Enclosing marks
R-0.1.6 Italicization
R-0.1.7 Elision and addition of vowels
R-0.1.8 Order of prefixes

This HTML reproduction is as close as possible to the published version [see IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC]. If you need to cite these rules please quote this reference as their source.

Published with permission of the IUPAC by Advanced Chemistry Development, Inc.,, +1(416)368-3435 tel, +1(416)368-5596 fax. For comments or suggestions please contact