Editing Alkane (section)

==Nomenclature==
{{Main|IUPAC nomenclature of organic chemistry}}
The [[IUPAC nomenclature of organic chemistry#Alkanes|IUPAC nomenclature]] (systematic way of naming compounds) for alkanes is based on identifying hydrocarbon chains. Unbranched, saturated hydrocarbon chains are named systematically with a Greek numerical prefix denoting the number of carbons and the suffix "-ane".<ref>{{cite book | chapter-url = http://www.acdlabs.com/iupac/nomenclature/93/r93_184.htm | access-date = 12 February 2007 | chapter = R-2.2.1: Hydrocarbons | author = IUPAC, Commission on Nomenclature of Organic Chemistry | title = A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993) | year = 1993 | publisher = Blackwell Scientific | isbn = 978-0-632-03488-8}}</ref>

In 1866, [[August Wilhelm von Hofmann]] suggested systematizing nomenclature by using the whole sequence of vowels a, e, i, o and u to create suffixes -ane, -ene, -ine (or -yne), -one, -une, for the [[hydrocarbons]] C<sub>''n''</sub>H<sub>2''n''+2</sub>, C<sub>''n''</sub>H<sub>2''n''</sub>, C<sub>''n''</sub>H<sub>2''n''−2</sub>, C<sub>''n''</sub>H<sub>2''n''−4</sub>, C<sub>''n''</sub>H<sub>2''n''−6</sub>.<ref>{{Cite web|url=http://www.chem.yale.edu/~chem125/125/history99/5Valence/Nomenclature/alkanenames.html|archiveurl=https://web.archive.org/web/20120202091842/http://www.chem.yale.edu/~chem125/125/history99/5Valence/Nomenclature/alkanenames.html|url-status=dead|title=Alkane Nomenclature<!-- Bot generated title -->|archivedate=2 February 2012}}</ref> In modern nomenclature, the first three specifically name hydrocarbons with single, double and triple bonds;<ref>Thus, the ending "-diene" is applied in some cases where von Hofmann had "-ine"</ref> while "-one" now represents a [[ketone]].

===Linear alkanes===
{{further|List of straight-chain alkanes}}
<!-- redirected from [[linear paraffins]] -->
Straight-chain alkanes are sometimes indicated by the prefix "n-" or "''n''-"(for "normal") where a non-linear [[isomer]] exists. Although this is not strictly necessary and is not part of the IUPAC naming system, the usage is still common in cases where one wishes to emphasize or distinguish between the straight-chain and branched-chain isomers, e.g., "[[butane|''n''-butane]]" rather than simply "butane" to differentiate it from [[isobutane]]. Alternative names for this group used in the petroleum industry are '''linear paraffins''' or '''''n''-paraffins'''.

The first eight members of the series (in terms of number of carbon atoms) are named as follows:
; [[methane]]: CH<sub>4</sub> – one carbon and 4 hydrogen
; [[ethane]] : C<sub>2</sub>H<sub>6</sub> – two carbon and 6 hydrogen
; [[propane]]: C<sub>3</sub>H<sub>8</sub> – three carbon and 8 hydrogen
; [[butane]] : C<sub>4</sub>H<sub>10</sub> – four carbon and 10 hydrogen
; [[pentane]]: C<sub>5</sub>H<sub>12</sub> – five carbon and 12 hydrogen
; [[hexane]] : C<sub>6</sub>H<sub>14</sub> – six carbon and 14 hydrogen
; [[heptane]]: C<sub>7</sub>H<sub>16</sub> – seven carbons and 16 hydrogen
; [[octane]]: C<sub>8</sub>H<sub>18</sub> – eight carbons and 18 hydrogen

The first four names were [[back-formation|derived]] from [[methanol]], [[diethyl ether|ether]], [[propionic acid]] and [[butyric acid]]. Alkanes with five or more carbon atoms are named by adding the [[Affix|suffix]] '''-ane''' to the appropriate [[IUPAC numerical multiplier|numerical multiplier]] prefix<ref name=reusch-nom>{{cite web | first = William |last=Reusch | work = Virtual Textbook of Organic Chemistry | title = Nomenclature – Alkanes | url = http://www.cem.msu.edu/~reusch/VirtualText/nomen1.htm | access-date = 5 April 2007 | archive-url = http://arquivo.pt/wayback/20160521131930/http://www.cem.msu.edu/~reusch/VirtualText/nomen1.htm | archive-date = 21 May 2016 | url-status = dead}}</ref> with [[elision]] of any terminal vowel (''-a'' or ''-o'') from the basic numerical term. Hence, [[pentane]], C<sub>5</sub>H<sub>12</sub>; [[hexane]], C<sub>6</sub>H<sub>14</sub>; [[heptane]], C<sub>7</sub>H<sub>16</sub>; [[octane]], C<sub>8</sub>H<sub>18</sub>; etc. The [[numeral prefix]] is generally Greek; however, alkanes with a carbon atom count ending in nine, for example [[nonane]], use the [[Latin language|Latin]] prefix '''non-'''.

===Branched alkanes===
[[Image:Isopentane-numbered-3D-balls.png|thumb|right|[[Ball-and-stick model]] of [[isopentane]] (common name) or 2-methylbutane (IUPAC systematic name)]]
Simple branched alkanes often have a common name using a prefix to distinguish them from linear alkanes, for example [[pentane|''n''-pentane]], [[isopentane]], and [[neopentane]].

IUPAC naming conventions can be used to produce a systematic name.

The key steps in the naming of more complicated branched alkanes are as follows:<ref>{{cite web | first = William |last=Reusch | work = Virtual Textbook of Organic Chemistry | title = Examples of the IUPAC Rules in Practice | url = http://www.cem.msu.edu/~reusch/VirtualText/nomexmp1.htm | access-date = 5 April 2007 | archive-url = http://arquivo.pt/wayback/20160521132003/http://www.cem.msu.edu/~reusch/VirtualText/nomexmp1.htm | archive-date = 21 May 2016 | url-status = dead}}</ref>
* Identify the longest continuous chain of carbon atoms
* Name this longest root chain using standard naming rules
* Name each side chain by changing the suffix of the name of the alkane from "-ane" to "-yl"
* Number the longest continuous chain in order to give the lowest possible numbers for the side-chains<ref>{{Cite web|url=http://www.chem.uiuc.edu/GenChemReferences/nomenclature_rules.html|title=IUPAC Rules|website=www.chem.uiuc.edu|access-date=13 August 2018}}</ref>
* Number and name the side chains before the name of the root chain
* If there are multiple side chains of the same type, use prefixes such as "di-" and "tri-" to indicate it as such, and number each one.
* Add side chain names in alphabetical (disregarding "di-" etc. prefixes) order in front of the name of the root chain

{| class="wikitable" style="text-align:center"
|+ Comparison of nomenclatures for three isomers of C<sub>5</sub>H<sub>12</sub>
|-
! Common name
! ''n''-pentane || isopentane || neopentane
|-
! IUPAC name
! pentane || 2-methylbutane || 2,2-dimethylpropane
|-
! Structure
| [[Image:Pentane-2D-Skeletal.svg|120px]] || [[Image:Isopentane-2D-skeletal.svg|90px]] || [[Image:Neopentane-2D-skeletal.png|70px]]
|}

===Saturated cyclic hydrocarbons===
{{Main|Cycloalkane}}

Though technically distinct from the alkanes, this class of hydrocarbons is referred to by some as the "cyclic alkanes." As their description implies, they contain one or more rings.

Simple cycloalkanes have a prefix "cyclo-" to distinguish them from alkanes. Cycloalkanes are named as per their acyclic counterparts with respect to the number of carbon atoms in their backbones, e.g., [[cyclopentane]] (C<sub>5</sub>H<sub>10</sub>) is a cycloalkane with 5 carbon atoms just like [[pentane]] (C<sub>5</sub>H<sub>12</sub>), but they are joined up in a five-membered ring. In a similar manner, [[propane]] and [[cyclopropane]], [[butane]] and [[cyclobutane]], etc.

Substituted cycloalkanes are named similarly to substituted alkanes – the cycloalkane ring is stated, and the substituents are according to their position on the ring, with the numbering decided by the [[Cahn–Ingold–Prelog priority rules]].<ref name=reusch-nom/>

===Trivial/common names===
{{main|List of straight-chain alkanes}}
The trivial (non-[[IUPAC nomenclature|systematic]]) name for alkanes is "paraffins". Together, alkanes are known as the "paraffin series". Trivial names for compounds are usually historical artifacts. They were coined before the development of systematic names, and have been retained due to familiar usage in industry. Cycloalkanes are also called naphthenes.<ref>{{Cite web|title=Definition of CYCLOALKANES|url=https://www.merriam-webster.com/dictionary/cycloalkanes|access-date=2021-06-26|website=www.merriam-webster.com|language=en}}</ref><ref>{{Cite web|title=Definition of NAPHTHENES|url=https://www.merriam-webster.com/dictionary/naphthenes|access-date=2021-06-26|website=www.merriam-webster.com|language=en}}</ref>

Branched-chain alkanes are called '''isoparaffins'''. "Paraffin" is a general term and often does not distinguish between pure compounds and mixtures of [[isomer]]s, i.e., compounds of the same [[chemical formula]], e.g., [[pentane]] and [[isopentane]].

;In IUPAC
The following trivial names are retained in the IUPAC system:
* [[isobutane]] for 2-methylpropane
* [[isopentane]] for 2-methylbutane
* [[neopentane]] for 2,2-dimethylpropane.

;Non-IUPAC
Some non-IUPAC trivial names are occasionally used:
* cetane, for [[hexadecane]]
* cerane, for [[hexacosane]]<ref>{{cite book |first=Donald |last=Mackay |title=Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals |date=14 March 2006 |isbn=1-4200-4439-7 |page=206|publisher=CRC Press }}</ref>