Non-pure alkanes have a taste.

Are all pure hydrocarbons tasteless, colorless and odorless? Are there hydrocarbons that do have a taste, color and/or odor?

If so, what makes these ones different, even though they are only made of carbon and hydrogen?

  • $\begingroup$ There are numerous hydrocarbons which are neither odorless nor tasteless. Some are moderately complex and exhibit chirality, such as pinene and limonene. However, even simpler achiral ones can, such as benzene and its various derivatives (the name "aromatic hydrocarbon" is not coincidental). $\endgroup$
    – Greg E.
    Mar 18, 2014 at 5:23
  • 2
    $\begingroup$ I think this is a good question maybe you could write the body better because it seems is going to be closed "for length and content". $\endgroup$
    – G M
    Mar 18, 2014 at 7:41

2 Answers 2


Why would a mixture of two odourless alkanes have an odour?

As already pointed out by Greg E and Uncle Al, numerous hydrocarbons without any (heteroatom-based) functional groups do show characteristic smells.

Naphthalene is always remembered for the typical smell of grandma's mothballs.

More pleasant smells are found in the group of monoterpenes, i.e. in those molecules with the sum formula $\ce{C10H16}$ that are derived from the combination of two isoprene units.


These volatile compounds were/are used as fragrances for perfumes. Typical examples are myrcene (1), $\alpha$-terpinene (2), limonene (3), $\alpha$-pinene (4), $\beta$-pinene (5), $\alpha$-thujene (6), sabinene (7), and camphene (8).

As far as the colour of hydrocarbons is concerned:

structure of lycopene

A sufficiently conjugated system is far from being colourless, take lycopene (9), the deep red coloured dye in tomatoes as an example.


Adamantane smells of camphor. n-Nonane is in the scent of some roses, see here.

  • $\begingroup$ This page says that it's odourless I think that the non-pure one smells of camphor and the pure one is odourless .. chemyq.com/En/xz/xz1/4626inphf.htm $\endgroup$
    – user37421
    Mar 18, 2014 at 4:16
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    $\begingroup$ @user37421 "This page" is a sloppy translation from Chinese to English with a garbled CAS no. In contrast to the article in a peer-reviewed journal, that Uncle Al linked in his answer, it is very unreliable. $\endgroup$ Mar 18, 2014 at 5:38

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