Cyanide and benzaldehyde both have an almond-like smell.

Some people cannot smell cyanide (specifically, HCN). Can they also not smell benzaldehyde?

In other words, do they both trigger the same receptors?

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    $\begingroup$ Hm. I think I know where you're getting the link from (they both smell like almonds). Let me see what I can find. $\endgroup$ Commented Jun 23, 2015 at 13:45
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    $\begingroup$ I perceive the smells as decidedly different. But of course when amygdalin is hydrolyzed both of them usually appear essentially together.Benzaldehyde is easy to get (almond aroma) - so you can check easily whether people can smell that. Cyanide is obviously more difficult. But if you take bitter almonds and hydroloyse the amygdalin in acidic condidtions (e.g. with KHSO4 added), cyanide smell will be available shortly before the benzaldehyde sets in. $\endgroup$ Commented Mar 25, 2017 at 10:01

1 Answer 1


Answer is, they are most probably not correlated. Smell requires molecules to bind to receptors, which they do by structure and functional group. CN is a very small linear molecule that does not even share its heteroatoms with benzaldehyde, an aromatic compound several times cyanide's size. Ergo, it's improbable they share the same scent receptors.

  • $\begingroup$ Then why do they smell very similar? $\endgroup$ Commented Jun 23, 2015 at 15:25
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    $\begingroup$ Uhm, are there people that cannot smell benzaldehyde? I think not. $\endgroup$
    – Jori
    Commented Jun 23, 2015 at 16:08
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    $\begingroup$ @Jori I have a friend who swears he cannot smell ammonia, so I guess anything is possible. $\endgroup$ Commented Jun 23, 2015 at 18:44
  • $\begingroup$ @orthocresol how can some say they cannot detect a stimulus in the first place? How would they know what to detect if they cannot detect it? $\endgroup$
    – Papul
    Commented Jun 25, 2015 at 18:49
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    $\begingroup$ To me they smell decidedly different (same for my father and brother - my moter smells benzaldehyde but not HCN). I've met several people who cannot smell HCN, but so far noone who cannot smell benzaldehyde (we tested with 50+ people in two seminars). $\endgroup$ Commented Mar 25, 2017 at 9:55

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