- IUPAC numerical multiplier
The numerical multiplier (or multiplying affix) in
IUPAC nomenclatureindicates 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.
The affix for a number larger than twelve is constructed is the opposite order to that which the number is written in
Hindu-Arabic numerals: units, then tens, then hundreds, then thousands. For example::548 → octa- (8) + tetraconta- (40) + pentacta- (500) = "octatetracontapentacta-":9267 → hepta- (7) + hexaconta- (60) + dicta- (200) + nonalia- (9000) = "heptahexacontadictanonalia-"
The numeral one
While the use of the affix "mono-" is rarely necessary in
organic chemistry, it is often essential in inorganic chemistryto 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 → hen- (1) + tetraconta- (40) + dicta- (200) = "hentetracontadicta-":411 → undeca- (11) + tetracta- (400) = "undecatetracta-"
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." eicosa-
IUPACprefers the spelling icosa- for the affix corresponding to the number twenty on the grounds of etymology. However both the Chemical Abstracts Serviceand the Beilstein databaseuse the alternative spelling "eicosa-".
"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, "khīlioi" = 1000, "diskhīlioi" = 2000, "triskhīlioi" = 3000, etc, and 13 to 19 are "treiskaideka" etc with the Greek for "and" inserted (as in triskaidekaphobia).
Wikimedia Foundation. 2010.
Look at other dictionaries:
IUPAC nomenclature of inorganic chemistry — For the current Red Book version, see IUPAC nomenclature of inorganic chemistry 2005. The IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure… … Wikipedia
Chemical nomenclature — A chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC). The… … Wikipedia
Alkane — Not to be confused with Alkene or Alkyne. Chemical structure of methane, the simplest alkane Alkanes (also known as paraffins or saturated hydrocarbons) are chemical compounds that consist only of hydrogen and carbon atoms and are bonded… … Wikipedia
Year — A year (from Old English gēar) is the orbital period of the Earth moving around the Sun. For an observer on Earth, this corresponds to the period it takes the Sun to complete one course throughout the zodiac along the ecliptic. In astronomy, the… … Wikipedia