IUPAC numerical multiplier

<h2 id="compound-affixes">Compound affixes</h2>
<p>The prefixes are given from the least significant decimal digit up: units, then tens, then hundreds, then thousands. For example:
</p>
548 → octa- (8) + tetraconta- (40) + pentacta- (500) = <i>octatetracontapentacta-</i>
9267 → hepta- (7) + hexaconta- (60) + dicta- (200) + nonalia- (9000) = <i>heptahexacontadictanonalia-</i>
<h3>The numeral one</h3>
<p>While the use of the affix <i>mono-</i> is rarely necessary in <a href="/facts/Organic_chemistry/djxhxaNg">organic chemistry</a>, it is often essential in <a href="/facts/Inorganic_chemistry/ErD6ypnb">inorganic chemistry</a> to avoid ambiguity: carbon oxide could refer to either <i><a href="/facts/Carbon_monoxide/CKuLtEMJ">carbon monoxide</a></i> or <i><a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a></i>. In forming compound affixes, the numeral one is represented by the term <i>hen-</i> except when it forms part of the number eleven (<i>undeca-</i>): hence
</p>
241 → hen- (1) + tetraconta- (40) + dicta- (200) = <i>hentetracontadicta-</i>
411 → undeca- (11) + tetracta- (400) = <i>undecatetracta-</i>
<h3>The numeral two</h3>
<p>In compound affixes, the numeral two is represented by <i>do-</i> except when it forms part of the numbers 20 (<i>icosa-</i>), 200 (<i>dicta-</i>) or 2000 (<i>dilia-</i>).
</p>
<h2 id="icosa--veicosa-">Icosa- <i>v.</i> eicosa-</h2>
<p><a href="/facts/IUPAC/2AV6myCK">IUPAC</a> prefers the spelling icosa- for the affix corresponding to the number twenty on the grounds of <a href="/facts/Etymology/18QG6y67">etymology</a>. However both the <a href="/facts/Chemical_Abstracts_Service/CVLrS5IJ">Chemical Abstracts Service</a> and the <a href="/facts/Beilstein_database/ABnkrCra">Beilstein database</a> use the alternative spelling <i>eicosa-</i>.
</p>
<h2 id="other-numerical-prefix-types">Other numerical prefix types</h2>
<p>There are two more types of numerical prefixes in IUPAC organic chemistry nomenclature.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a>
</p>
<h3>Numerical terms for compound or complex features</h3>
<p>Numerical prefixes for multiplication of compound or complex (as in <i>complicated</i>) features are created by adding <i>kis</i> to the basic numerical prefix, with the exception of numbers 2 and 3, which are bis- and tris-, respectively.
</p>
<table><tbody><tr><th>Number</th><th>Multiplier</th></tr><tr><td>2</td><td>bis-</td></tr><tr><td>3</td><td>tris-</td></tr><tr><td>4</td><td>tetrakis-</td></tr><tr><td colspan="2">...</td></tr></tbody></table>
<p>An example is the IUPAC name for <a href="/facts/DDT/RfYXlCuF">DDT</a>.
</p>
<h3>Multiplicative prefixes for naming assemblies of identical units</h3>
<table><tbody><tr><th>Number</th><th>Multiplier</th></tr><tr><td>5</td><td>quinque-</td></tr><tr><td>6</td><td>sexi-</td></tr><tr><td>7</td><td>septi-</td></tr><tr><td>8</td><td>octi-</td></tr><tr><td>9</td><td>novi-</td></tr><tr><td>10</td><td>deci-</td></tr><tr><td>11–9999</td><td><i>Ending "a" in the basic numerical prefixis replaced with "i",and/or "deka" is replaced with "deci".</i> </td></tr></tbody></table>
<p>Examples are <a href="/facts/Biphenyl/WWuTjvpd">biphenyl</a> or <a href="/facts/Terphenyl/1SrQYTkh">terphenyl</a>.
</p>
<h2 id="etymology">Etymology</h2>
<p>"mono-" is from <a href="/facts/Greek_language/pzDd6eIz">Greek</a> <i>monos</i> = "alone". "un" = 1 and "nona-" = 9 are from <a href="/facts/Latin/pM3Kge85">Latin</a>. The others are derived from Greek numbers.
</p><p>The forms 100 and upwards are not correct Greek. In <a href="/facts/Ancient_Greek/LIK7NlUh">Ancient Greek</a>, <i>hekaton</i> = 100, <i>diakosioi</i> = 200, <i>triakosioi</i> = 300, etc. The numbers 200-900 would be confused easily with 22 to 29 if they were used in chemistry.
</p><p><i>khīlioi</i> = 1000, <i>diskhīlioi</i> = 2000, <i>triskhīlioi</i> = 3000, etc.
</p><p>13 to 19 are formed by starting with the Greek word for the number of ones, followed by <i>και</i> (the Greek word for 'and'), followed by <i>δέκα</i> (the Greek word for 'ten'). For instance <i>treiskaideka</i>, as in <a href="/facts/Triskaidekaphobia/QovBNCUu">triskaidekaphobia</a>.
</p>
<h2 id="notes-and-references">Notes and references</h2>
<ul><li>Panico, R. & Powell, W. H., eds. (1994). <i>A Guide to IUPAC Nomenclature of Organic Compounds 1993</i>. Oxford: Blackwell Science. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-632-03488-2.</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>IUPAC Blue Book, 2013 <a href="/wiki/IUPAC_Blue_Book" target="_blank">/wiki/IUPAC_Blue_Book</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
</ol>

IUPAC numerical multiplier open-in-new

IUPAC numerical multiplier