Uploaded May 2017 | Updated September 2026, 1 week ago
Before you watch: There is no visible reaction!
Palladium has a strong affinity towards Sulphur. Reactions including both are said to be exothermic. We tried it with Selenium, we tried it with Tellurium and in these cases, we saw a reaction. For Sulphur, however, we could not observe any visible change in two runs. The only reaction being a combustion while we heat the sulfur which indicates a reaction happening. But as you see in the second run we even had the Pd in molten Sulphur and nothing happened.
The reaction is said to start at much higher temperatures so we might try this again with direct heating.
The phase diagram also tells that below 30% Pd not much is going to happen util a PdS2 might form. The mixture has an eutectic point at about 630°C with 70% Pd and all other mixtures are way above that which is why the Pd was able to just float in the molten Sulphur without a reaction.
As always, if you managed to react those two or have a suggestion we are always open to good ideas!
Before you watch: There is no visible reaction!
Palladium has a strong affinity towards Sulphur. Reactions including both are said to be exothermic. We tried it with Selenium, we tried it with Tellurium and in these cases, we saw a reaction. For Sulphur, however, we could not observe any visible change in two runs. The only reaction being a combustion while we heat the sulfur which indicates a reaction happening. But as you see in the second run we even had the Pd in molten Sulphur and nothing happened.
The reaction is said to start at much higher temperatures so we might try this again with direct heating.
The phase diagram also tells that below 30% Pd not much is going to happen util a PdS2 might form. The mixture has an eutectic point at about 630°C with 70% Pd and all other mixtures are way above that which is why the Pd was able to just float in the molten Sulphur without a reaction.
As always, if you managed to react those two or have a suggestion we are always open to good ideas!
![Mercury Chemistry: Co[Hg(SCN)4]](https://i.ytimg.com/vi/jUqjZziourY/mqdefault.jpg "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 say this could also be Co(SCN)x. True, they have a similar color. But we made the Thiocyanatocobaltate(II) about 2-3 years ago and since then left it on the shelf and it never precipitated. While here we have a much lower conc. of Co(II). Hg(SCN)2, on the other hand, is not colored because Hg(II) is a d10-system.")
![Mercury Chemistry: Hg3[AsO3]2 and Hg3[AsO4]2](https://i.ytimg.com/vi/kCN6V7e5-Eo/mqdefault.jpg "Mercury Chemistry: Hg3[AsO3]2 and Hg3[AsO4]2
In this video, we make and compare a Mercury(II)-Arsenite and -Arsenate by mixing HgCl2 with NaAsO2 and NaHAsO4. Now usually we do not make every possible compound just to increase the number of videos but for this, we wanted to test something. The Arsenate is, according to literature yellow, while the Arsenite is colorless, but develops a yellow color which is believed to be due to oxidation. We wanted to test this and made both solutions.
At first, you cannot see any precipitate (right jar = Arsenate) but after a while, and a second addition of more Arsenate you can see a yellow turbid color. For the Arsenite, it happens much fast but the solution turns yellow as well, much as expected. If you compare the two after a while you can see that they have the same type of yellow in their solution. 24h later the Arsenate had precipitated as yellow compound while the Arsenite formed a colorless one.
This proves, that the compounds differ in color and only a small fraction, the parts in solution are yellow, probably due to oxygen in the water and the stirring process and that it probably is some oxidation of the Arsenite.
We also tested both up to 350°C for thermochromism but nothing happened.")
