Hello, guys! Today new unique chemical reactions are waiting for you.
I'm sure you haven't seen any of these before,
because the chemical reagent of this episode is very rare and expensive.
Today I'm going to show you a cool chemical reactions pack with rhenium heptoxide
Rhenium heptoxide is the oxide of one of the rarest metal called Rhenium.
This compound is rhombic crystals of lemon-yellow color.
This is a volatile solid matter that is easy to deliquesce in the air.
It's very rare and expensive chemical reagent, Sigmaaldrich sells it for about $100 per gram
My sample in a sealed glass ampoule contains 10 grams of pure Rhenium (VII) oxide
Rhenium heptoxide crystals have the properties
that are typical of molecular ones: low stability of crystal lattice, and low melting and boiling points.
When heated to 300°C rhenium heptoxide sublimates
and settles down on colder tube's walls
Look how beautifully rhenium heptoxide is crystallizing!
Unlike its group neighbour Mn2O7, Rhenium (VII) oxide is not a strong oxidizer.
One of the few matters that are oxidized is bromine from hydrobromic acid
As strange as it is, I didn't happen to have hydrobromic acid,
so I had to get it.
And how do true chemists get their hydrogen bromide?
Exactly! Hydrolysis of boron tribromide
Boron tribromide is a fuming liquid compound,
it is decomposed by water and forms hydrogen bromide and boric acid.
Let's add some crystals of rhenium heptoxide into hydrogen bromide solution.
The reaction takes place in a boiling solution.
rhenium (VII) oxide reacts with hydrogen sulfide instantly at the room temperature
forming black rhenium sulphide
Burned down in air, Rhenium sulphide forms Rhenium trioxide and white smoke that consists of Re2O7 particles.
In this reaction we'll get Rhenium trioxide by decomposing the solvate with a Re2O7and dioxane
One can also get it by decomposing Re2O7 solvates
with such matters as: ethyl alcohol, acetyl acetone, pyridine, tetrahydrofuran, etc.
Rhenium trioxide - It is a red solid with a metallic lustre
which resembles copper in appearance. It is the only stable trioxide of the Group 7
For maximum yield, we're heating the precipitation we got in oxygen flow
Here you may also see formed rhenium seven oxide, that we already know well
Blue stain that appears occasionally is probably a matter of unstable mixed Re2O7*ReO3
-type oxide forming during the process
rhenium trioxide reacts with nitric acid to form nitrogen dioxide
Being dissolved in water, Re2O7 forms a strong monobasic perrhenic acid
Thus, formed perrhenic acid dissolves metallic to form magnesium perrhenate and hydrogen
If we add hydrazine hydrate to rhenium acid dark-brown, almost black rhenium dioxide can be obtained
One of the first suugested qualitateve reaction for rhenium (whether it's perrhenate ions or rhenium ions)
was the interreaction of thiocyanate ions with tin(II) chloride and a hydrochloric acid solution containing any compounds of rhenium.
As a result, the colour changes from yellow to orange
The complex that is formed in this reaction is extracted with diethyl ether.
It is used in analytical chemistry of rhenium
At the beginning of the video you saw Re2O7 melting and sublimation,
but it sublimates without melting in oxygen flow,
forming thin rhombic crystals. It looks amazing
Hi, dexxterius. I read your comment where you suggest a mixture for extra-exotic termite consisting of Re2O7 and Hf.
I did it and I will share the result of this experiment in the next video, that’s why subscribe to channel to make sure you don't miss it.
See you there