Hello, everyone! today we will conduct interesting and very expensive experiments with rubidium.
Rubidium is an active alkali metal,
which is in the first group of the periodic table of chemical elements, below potassium.
Due to its extremely high activity
Rubidium is stored in glass ampoules under vacuum or inert atmosphere such as argon.
In the vial you can observe the shiny surface of rubidium. [Russian text: "Condensation droplets of Rubidium"]
Before we conduct our experiments with rubidium it must be removed from the ampoule.
However the ampoule must of course be first opened to do that.
In order to open it I took a file and scratched the ampoule to get a more flattened crack later on.
Then I hit the ampoule with a hammer, and now it’s open.
However our rubidium is still trapped inside!
To finally get it out of there I used the small melting point of rubidium, which is 39.3°C (312.45 K / 102.7°F).
I heated the vial with the rubidium inside with a torch and poured of the resulted molten metal into the jar of kerosene.
Because Kerosene has water and oxygen impurities in it,
Rubidium oxidized very rapidly even in Kerosene and becomes coated with a layer of Peroxides.
Rubidium is an incredibly soft metal. Its hardness resembles a butter at room temperature.
Now let's conduct some chemical reactions with it.
To get started simply cut off a piece of rubidium and leave it on a napkin.
Because of the oxidation with oxygen, rubidium melts by the heat of the reaction.
In this case rubidium might become self-igniting,
setting flames to everything surrounding it.
If you take a large piece of rubidium and leave it on a wooden surface,
it will then firstly melt and later self-ignite, burning with a beautiful violet flame
because of the rubidium ions.
In water rubidium behaves much more dangerously than potassium.
If you throw even a small piece of rubidium in water,
an explosion will immediately occur.
Because rubidium is much denser at water and has a very low melting point, [and it is also a very active metal].
Large pieces of Rubidium vigorously explode in water
I had also conducted a reaction with rubidium and sand, similar to lithium.
However, rubidium simply melted of the hot sand without any combustion.
Rubidium still reacted with the sand to form an amorphous silicon (from the silicon dioxide) that the sand consists of.
A beautiful effect was when rubidium was somewhat absorbed in the sand to form a shiny metal surface.
Even more interesting was the reaction of rubidium with sulfur.
At first I just set fire to the rubidium with sulfur,
and the reaction was pretty rough
Then I have melted the sulfur and added pieces of rubidium to it,
rubidium burned in the sulfur to form beautiful sparks of molten metal.
Finally, to remove the leftover rubidium from the jar, I filled it with alcohol.
In this case rubidium immediately ignited the alcohol because of the violent reaction,
but then the reaction became more calm.
Also, due to the strong alkaline environment the alcohol was colored orange
Nowadays the Metal rubidium has little practical application
primarily because of the high cost and a few places to buy it.
The cost of the ampoule with rubidium that I experimented with was around 500 €.
Usually rubidium and its compounds are used in organic synthesis, optics and nuclear industry.
Also, vapours of rubidium are used in the high-precision rubidium clocks that are of extremely low error.
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A big thank you to the facility of Chemistry Chemicum at the University of Tartu for the provided rubidium for our experiments.