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I know that in a compound, when there are two double/triple bonds its like :

1,3-diene ; 1,3-diyne and so on.

For three :

1,3,5-triene ; 1,3,5-triyne and so on.

But what about 4?

While doing a question I encountered this :

2,4,6,8-(What?)ene

Is it quad,quart,quater(like quaternary carbon) or something else?

Also, it would be helpful if you could extend it to like 5 or as much as you can double/triple bonds.

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  • $\begingroup$ For four use tetra and after, penta, exa, hepta, octa, nona, deca, undeca and so on :-) $\endgroup$ – ParaH2 Oct 6 '16 at 12:33
  • $\begingroup$ @9-BBN typo: exa > hexa $\endgroup$ – DHMO Oct 6 '16 at 12:50
  • $\begingroup$ Yes @DHMO hexa ! :) $\endgroup$ – ParaH2 Oct 6 '16 at 12:58
4
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The multiplying affixes are given by Table 11 of the Blue Book, referenced in R-0.1.4 and R-4.1:

Number  Numerical term | Number  Numerical term
1       mono-          | 90      nonaconta-
2       di-            | 100     hecta-
3       tri-           | 200     dicta-
4       tetra-         | 300     tricta-
5       penta-         | 400     tetracta-
6       hexa-          | 500     pentacta-
7       hepta-         | 600     hexacta-
8       octa-          | 700     heptacta-
9       nona-          | 800     octacta-
10      deca-          | 900     nonacta-
11      undeca-        | 1000    kilia-
12      dodeca-        | 2000    dilia-
20      icosa-         | 3000    trilia-
30      triaconta-     | 4000    tetralia-
40      tetraconta-    | 5000    pentalia-
50      pentaconta-    | 6000    hexalia-
60      hexaconta-     | 7000    heptalia-
70      heptaconta-    | 8000    octalia-
80      octaconta-     | 9000    nonalia-

Therefore, the answer to your question is 2,4,6,8-tetraene.


Extra information

Note that there is no elision of vowels, specified by R-0.1.7:

R-0.1.7.1 Vowels are systematically elided as follows:

(a) the terminal "e" in names of parent hydrides when followed by a suffix beginning with "a", "i", "o", "u", or "y";

(b) in the Hantzsch-Widman system, the final "a" of an element prefix when followed by a vowel;

(c) the terminal "a" in the names of numerical multiplicative affixes when followed by a suffix beginning with "a" or "o", or a Hantzsch-Widman prefix or stem beginning with a vowel;

(d) the terminal "a" of an element prefix in "ababa" repeating unit names (see R-2.3.3.2) and the terminal "o" of a replacement infix when followed by a vowel;

The relevant part is (c), which states that the final "a" in the above affixes are elided when the next letter is "a" or "o", but in this case the next letter is "e" so it is not elided.

The following are given examples of elision:

  • benzenehexaol > benzenehexol
  • [1,1'-binaphthalene]-3,3',4,4'-tetraamine > [1,1'-binaphthalene]-3,3',4,4'-tetramine
  • 1,3,5,7-tetraoxaocane > 1,3,5,7-tetraoxocane
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  • $\begingroup$ Please note that this nomenclature is 1993 standard. $\endgroup$ – DHMO Oct 6 '16 at 13:34

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