Mercury Chemistry: Co[Hg(SCN)4]

In this video, we make an interesting compound Co[Hg(SCN)4]. It is prepared by mixing a Hg solution with NH4SCN and adding some CoCl2. The compound does not form right away but after a while, tiny blue parts can be seen all over the solution. They quickly fall to the bottom where after a night bigger flakes had formed as well. As you can the solution is clear in the end, so all the CoCl2 has reacted to form the insoluble Co[Hg(SCN)4]. As they grow so slowly often bigger crystals can be made. Now you might