2
$\begingroup$

Apparently this video is a reaction of $\ce{NH4Cr2O7}$ with $\ce{HgSCN}$.

The title of the video suggests the reaction opens a portal to hell, but I am pretty sure that is not the case.

What exactly goes on in the reaction?

$\endgroup$
1
  • 2
    $\begingroup$ In short, this is a mash-up of two well-known experiments: Pharaoh's serpent and Vesuvian fire. The two compounds do not really react with each other (well, at least not much); instead, each reacts on its own. $\endgroup$ Feb 25, 2016 at 16:57

1 Answer 1

2
$\begingroup$

I can't comment on the metaphysical aspects ;)

This experiment is known as Pharaoh's snakes, and it is indeed impressive.

Upon heating, mercury thiocyanate decomposes to yield mercury vapour, carbon sulfide, and dicyan (ethanedinitrile):

$$\ce{2Hg(SCN)2 ->[\Delta] 2 Hg + 2CS2 + (CN)2}$$

As a result, the solid starting turns to a foam-like mass.

The effect is amplified due to the presence of ammonium dichromate, which oxidizes the carbon disulfide to sulfur dioxide and carbon dioxide.

The experimenter is apperently aware that quite a lot of rather harmful components are released and therefore has decided to run the show in the fumehood and closes the window immediately after igniting the mixture.

$\endgroup$
1
  • 1
    $\begingroup$ None of those products looks nice, but the cyanogen may just open a one-way portal to hell for some. $\endgroup$ Feb 25, 2016 at 22:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.