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IUPAC numerical multiplier The numerical multiplier (or multiplying affix) in IUPAC nomenclature indicates how many particular atoms or functional groups are attached at a particular point in a molecule. The affixes are derived from both Latin and Greek.
Contents Compound affixes The numeral one The numeral two Icosa- v. eicosaOther numerical prefix types Numerical terms for compound or complex features Multiplicative prefixes for naming assemblies of identical units Etymology See also Notes and references
Compound affixes
Number
The numeral one While the use of the affix mono- is rarely necessary in organic chemistry, it is often essential in inorganic chemistry to avoid ambiguity: carbon oxide could refer to either carbon monoxide or carbon dioxide. In forming compound affixes, the numeral one is represented by the term hen- except when it forms part of the number eleven (undeca-): hence
241 Õ hen- (1) + tetraconta- (40) + dicta- (200) = hentetracontadicta411 Õ undeca- (11) + tetracta- (400) = undecatetracta-
Number
Multiplier
1
mono-
32
dotriaconta-
2
di-
40
tetraconta-
3
tri-
50
pentaconta-
4
tetra-
60
hexaconta-
5
penta-
70
heptaconta-
6
hexa-
80
octaconta-
7
hepta-
90
nonaconta-
8
octa-
100
hecta-
9
nona-
200
dicta-
10
deca-
300
tricta-
11
undeca-
400
tetracta-
12
dodeca-
500
pentacta-
13
trideca-
600
hexacta-
14
tetradeca-
700
heptacta-
pentadeca-
800
octacta-
hexadeca-
900
nonacta-
17
heptadeca-
1000
kilia-
18
octadeca-
2000
dilia-
19
nonadeca-
3000
trilia-
20
icosa-/eicosa-
4000
tetralia-
21
henicosa-/heneicosa-
5000
pentalia-
22
docosa-
6000
hexalia-
23
tricosa-
7000
heptalia-
30
triaconta-
8000
octalia-
31
hentriaconta-
9000
nonalia-
The affix for a number larger than twelve is constructed in the opposite order to that which the number is written in Hindu-Arabic numerals: units, then tens, then 15 hundreds, then thousands. For example: 16
548 Õ octa- (8) + tetraconta- (40) + pentacta- (500) = octatetracontapentacta9267 Õ hepta- (7) + hexaconta- (60) + dicta- (200) + nonalia- (9000) = heptahexacontadictanonalia-
Multiplier
The numeral two In compound affixes, the numeral two is represented by do- except when it forms part of the numbers 20 (icosa-), 200 (dicta-) or 2000 (dilia-).
Icosa- v. eicosaIUPAC prefers the spelling icosa- for the affix corresponding to the number twenty on the grounds of etymology. However both the Chemical Abstracts Service and the Beilstein database use the alternative spelling eicosa-.
Other numerical prefix types There are two more types of numerical prefixes in IUPAC organic chemistry nomenclature.[1]
Numerical terms for compound or complex features Numerical prefixes for multiplication of compound or complex (as in complicated) are created by adding kis to the basic numerical prefix, with the exception of numbers 2 and 3, which are bis- and tris-, respectively. Number
Multiplier
2
bis-
3
tris-
4
tetrakis-
... An example is the IUPAC name for DDT.
Multiplicative prefixes for naming assemblies of identical units Number
Multiplier
2
bi-
3
ter-
4
quater-
5
quinque-
6
sexi-
7
septi-
8
octi-
9
novi-
10
deci-
11–9999
Ending "a" in the basic numerical prefix is replaced with "i", and/or "deka" is replaced with "deci".
Examples are biphenyl or terphenyl.
Etymology "mono-" is from Greek monos = "alone". "un" = 1 and "nona-" = 9 are from Latin. The others are derived from Greek numbers. Linguists should note that the forms 100 and upwards are not correct Greek. In Ancient Greek, hekaton = 100, diakosioi = 200, triakosioi = 300, etc. The numbers 200-900 would be confused easily with 22 to 29 if they were used in chemistry. khīlioi = 1000, diskhīlioi = 2000, triskhīlioi = 3000, etc., and 13 to 19 are treiskaideka etc. with the Greek for "and" inserted (as in triskaidekaphobia).
See also oligopeptide — few polypeptide — many
Notes and references Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2. 1. IUPAC Blue Book, 2013 Retrieved from "https://en.wikipedia.org/w/index.php?title=IUPAC_numerical_multiplier&oldid=803273141"
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