> chemistry > divers-inorganiques > selenium-chemisty-red-black-transformations-chemicalforce

Selenium. Red-Black Transformations

ChemicalForce - 2023-06-26

Hey! One of My next videos will be about selenic acid H2SeO4, but for now I have prepared reactions with elemental selenium for you. While you're watching this video, I'm trying to get rid of the smell of garlic :D
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0:00 Intro
0:32 Selenium demonstration
1:50 Selenium plasma
2:53 Formation of selenium granules
5:42 Plastic selenium
6:15 Red selenium synthesis
9:25 Combustion of selenium in pure oxygen
10:15 Selenium dioxide and its reaction with anhydrous hydrazine
13:02 Selenium and nitric/sulfuric/iodic acid reactions
14:25 Selenium and alkali metals
15:41 Qualitative reaction to hydrogen selenide
16:34 Selenium tetrachloride 

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@AJ-qv9yo - 2023-06-26

Beautiful as always. You manage to get the most beauty out even "dull" elements. Se sits in my element collection, and now I enjoy all the beauty of it. Every element has its own internal beauty and fascination one only needs to get it to shine.

@herrhaber9076 - 2023-06-27

Selenium ? Dull ? Watch the movie Evolution with David Duchovny ;)
(Or if you have pityriasis versicolor then SeS2 is a lifelong friend)
Joke aside, you are right and as always I saw reactions I wouldnt even have thought of without Chemical Force.

@ajingolk7716 - 2024-06-26

☣☢⚠️

@lucasfortier3682 - 2023-06-26

Shit i didn't want the video to end.
Chemistry community loves you man.

@pyr0duck676 - 2023-06-27

Two reasons I love your videos:

1. They are AMAZING works of art! Have you considered entering in a scientific art competition?

2. I love that you explore lesser known reagents and compounds. There are so many chemistry YouTubers who have videos on nitric acid, sulfuric acid, magnesium combustion, thermite, etc. But how many YouTubers demonstrate selenium compounds reacting with anhydrous hydrazine? Only Chemical Force! Keep up the wonderful work!!!

Also, could you do a video exploring the various xenon compounds? That might be interesting!

@prapanthebachelorette6803 - 2023-06-27

Because he IS the force 😉

@helldad4689 - 2023-06-27

Who would even compete against him in an art competition? He is a league of his own

@ChemicalForce - 2023-06-27

Creating a video about xenon chemistry would be quite expensive, considering the average number of views on the channel :(
Currently, I don't have plans to produce such a video, but I hope to cover this topic in the future to close that gestalt :D

@SciDOCMBC - 2023-07-19

I also think that his videos are great, especially because he sometimes combines very exotic reaction partners. In defense of the other chemistry Youtubers however one has to admit that reagents such as thionyl chrlord for example, which is very often used in labs, are sometimes very difficult to obtain for private individuals.

@SciDOCMBC - 2023-07-19

​@@PaonporteurTo be honest, I don't really understand your hateful words against NileRed. In any case, I am also deeply disappointed by Chemical Force's reaction to your comment. What did NileRed do to get overthrown? He has over 5.6 million subscribers. So many Youtubers seem to be interested in it. Many users here are only interested in the reactions shown being as violent as possible. However, NileRed subscribers are interested in syntheses and their explanation and not that it splashes, cracks and burns as violently as possible. There should be enough space for everyone on YouTube and with your comment you only make yourself look ridiculous. This is not about a royal title, but about science. Your comment alone shows that you are not interested in the science itself, but in the loud boom.

@daltonsoutherland8836 - 2023-06-26

Why do you not have 10 million subscriber your the best chemistry channel on YouTube bro 😉❤️

@elliotwilliams7523 - 2023-06-27

Got to be the accent. We really like what we see. So many reactions we knew could happen just didn’t get to try. I love it

@1st_ProCactus - 2023-06-27

*you're

@ignilc - 2023-06-27

because people like to watch nilered's stupid videos

@Antinoüs-Dionysos - 2023-06-27

​@@elliotwilliams7523the accent makes it more authentic

@daltonsoutherland8836 - 2023-06-27

@@1st_ProCactus thanks for the correction dickhead 😂

@alexhatfield2987 - 2023-06-26

Peerless. I await CF new uploads like an 8 year old boy waiting for Xmas, and I’m never disappointed.

@raiyiar - 2023-06-26

the sculpture of the molten selenium poured into water first gave me praying mantis vibes, then you turned it on its side, and it resembled a keith haring style drawing :O love the stuff

@executive - 2023-06-26

it's amazing seeing the solid, liquid and gas phases of a metalloid all together at relatively low temperatures. Fantastic footage.

@aformalevent - 2024-03-14

I absolutely love your work. The videography is such high quality that it's a joy to watch these beautifully captured reactions. Be proud of what you do man! Elevating youtube chemistry to be heights on style.

@Kyu_97 - 2023-06-27

Your videos should be used by universities and highschools to showcase the different elements in class, for real I looove your work, I wish chemistry was a more popular topic on YouTube 😢

@terribleterrier1685 - 2023-06-27

Always the best surprise to see a new ChemcalForce in my notifications. Your editing, visual fidelity, and music are honestly amazing.

@Vile_Entity_3545 - 2023-06-26

You have just gotta love this channel

@GrumpyOrc - 2023-07-24

Beautiful reaction footage as always, the way red Selenium forms such larger crystals was especially interesting.

And I'm never going to get tired of watching anhydrous hydrazine react with things.

@natuhaysertkaya3391 - 2023-06-26

I would have loved to see selenium and sulphur melted together in varying ratios and tested for its material properties. Also would have liked to see arsenic and selenium reactions.

@drhaese - 2023-09-16

Many thanks for the exciting demonstration of the fascinating world of Se and its inorganic reactions.

@paranoiia8 - 2023-06-26

Amazing red color... So deep and vivid.

@pezboy715 - 2023-06-27

1:25 “resembling erythrocytes”??? Damn, you’re a well-educated man beyond just chemistry, it seems! Best chemistry channel on YT

@j_sum1 - 2023-06-27

Intriguing and unusual colours. Amazing shapes formed. Just beautiful.

@masterluc - 2023-07-01

I enjoy the beauty of - and cannot imagine the effort that goes into your videos.

@mikestewart4752 - 2023-06-26

Selenium was used in photocopiers just before I got into the industry. Would love to see some electro/photochemical reactions!

@takingthescenicroute1610 - 2023-06-27

One probably still finds a coating of it on the print drums of laser and LED printers.
The drum is first charged with a high voltage corona wire or charging roller.
The Se becomes conductive and locally grounds out the charge wherever light contacts it.
The parts of the drum still charged attract the oppositely-charged toner particles.

@mikestewart4752 - 2023-06-27

@@takingthescenicroute1610 I believe selenium was phased out due to toxicity concerns. I worked for a Japanese manufacturer and anything manufactured post 2010 had switched to a photosensitive polymer coating that would, like you say, take on an electrical charge from the corona wire. I believe the digitalization of the process that also contributed to selenium’s falling out of use. I’ve definitely seen what you are referring to though… The “Good Ol’ Days” 🙂☮️ from 🇨🇦

@DragonsAndDragons777 - 2023-06-26

I never even knew about Selenium

Edit: Those explosions are amazing!

@TheTransporter007 - 2023-06-26

Always a good day when ChemForce posts!

@artsmith1347 - 2023-12-19

Very nice photography and good choice of music. Thank you.

@KomradZX1989 - 2023-06-27

Your videos are absolutely the best bar none ❤❤❤

@gerry4b - 2023-06-27

It's rare to discover true beauty in life... thanks for sharing.

@SaunaShruti - 2023-06-26

U explain and demonstrate the experiments so well. U r really a genius guy. Keep up with your good work.

@ИванГригорьев-х4б - 2023-09-11

Beautiful! Fantastic work! 👍👍👍

@jimsvideos7201 - 2023-06-28

Gorgeous cinematography.

@Fredpotts - 2023-06-27

Organo-selenium compounds are easily absorbed through the skin. I once did an oxidation or an aldehyde with SeO2. I must have absorbed some of the reaction products because I smelled like a skunk for two weeks.

@chriswalford4161 - 2023-08-01

…., whereas you normally smell like what?

@Fredpotts - 2023-08-02

@@chriswalford4161 More like a civet...

@ukeedge2761 - 2024-03-06

​@@chriswalford4161i guessing not a skunk, dont be du mb. Please not here.

@TheDriller-Killer - 2024-03-15

@Fredpotts It's the same with Tellurium, there's an old saying amongst chemists, that you can tell if somebody has been working with the stuff, when they enter a room. 😂😂😂

@reverendtfg6802 - 2023-06-26

How does this guy not have millions of subscribers???

@1st_ProCactus - 2023-06-27

Absolutely one of the most bizarre elements. As usual excellent showcase

@robertmonroe9728 - 2023-06-26

The easiest way of getting red selenium is dissolving the black one in concentrated hot alkali or even melt with it. Then dissolveing in water you will get bright red solution of polyselenites and polyselenides. After adding any acid, sulphuric or muriatic, you will get red form

@amiralozse1781 - 2023-06-27

your videos are a form of art:
Chemical Art !

@TrippyMCT - 2023-06-27

Great video as always. Love the hoodie!

@shrivanth6774 - 2023-06-27

Akh I am not ready for this it's extremely heart 💓 warming

@borgmardunkleson2225 - 2023-06-27

how this channel doesnt have more subs is criminal

@rhagchem3650 - 2023-06-26

Your interpretation is very simplistic. What is red selenium?

1) There are two allotropes of selenium. Crystalline monoclinic red forms of Se8 and gray hexagonal. Then we have amorphous forms that can appear red, therefore quickly turn black when heated. Crystalline forms cannot be prepared by reducing Se4+ (N2H4, SO2).

Gray selenium is produced by very slow crystallization of liquid selenium.

Red selenium Se8 can be obtained from a "solution of selenium in sulfuric acid" and its recrystallization from carbon disulfide. "Amorphous red selenium" is not soluble in carbon disulfide.


Rapid cooling of the melt yields amorphous selenium as a glassy mass...sometimes called vitreous selenium, which is usually sold to chemists.


2) The reaction with sulfuric acid can be complicated:

8 Se + H2SO4 = (Se8 2+) + 2 (HSO4 -) + 2 H2O + SO2

and reaction with water:

(Se8 2+) + SO2 + 2 H2O = Se8 + H2SO4 + 2 (H +)

SO2:
(only what remained in solution after the reaction)

or

8 (Se8 2+ ) + 8 H2O = 7 Se8 + 8 H2SeO3 + 16 (H + )

The green solution is because it probably contains ions (Se 82+) and probably also others, e.g. (Se4 2+) ...

@ChemicalForce - 2023-06-27

I really wanted to obtain crystalline selenium to demonstrate it in the video. However, I encountered a challenge: selenium is only slightly soluble in CS2, requiring a large amount of the solvent to yield noticeable results.
When shaking red selenium with CS2, the latter turns yellowish, possibly due to its dissolution.
An alternative approach could involve using SeOCl2 to obtain crystalline red selenium, as it dissolves it much more effectively. However, I couldn't find information about this method, which may be attributed to the rarity of the reagent.

@GenosseRot - 2023-06-28

@@ChemicalForce The black amorphous selenium is slightly soluble in CS2. If you mix the black selenium (I strongly advise to use the black selenium you made from quickly cooling the molten selenium) ground it up to a fine powder and let it stir for a while in CS2 at least some of it should go into solution. The you can let the solution evaporate slowly (maybe in a crystallizing dish with a watch glas over it, so that only a small opening is left) you should see the formation of red crystals which are either alpha or beta red selenium (depends on the evaporation speed and temperature). I can imagine that it can look quite nice.

Another thing to think about is the forgotten third but most important modification of selenium: Gray selenium. This is the most stable form of selenium and it is a metalloid with semi-conducting properties. It was the first material where the photovoltaik-effect was observed. If you connect 2 wires to it and give it a little bit of voltage you should see that the current changes greatly depending on the amount of light that gets to the material. Grey selenium can be made by heating any form of selenium to ~ 180 °C for some time or by cooling down molten selenium slowly. This stuff is then not so glassly like the black selenium (amorphous) you have shown.

Either way: Great video! I'm a selenium chemist and it was a great joy to see you making some stuff with it. Maybe selenium won't have its last show on your channel with the H2SeO4 video? I would like it very much. It is a very interessting element and I would like to see more ;)

@rhagchem3650 - 2023-06-28

@@GenosseRot Beautiful gray selenium crystals can be found on tailings coal dumps.

@rhagchem3650 - 2023-06-28

@@ChemicalForce Yes, it's a bit of a problem! Selenium is not a big chemical topic. :) SeOCl2 is a relatively exotic substance. I used to be looking for information about this. Maybe here, you probably know. Publication: Monoclinic selenium crystal growth (cannot insert doi). Where it is claimed that selenium is "well" soluble in methylene iodide.

@ChemicalForce - 2023-06-28

​@@GenosseRot there will be at least two more videos about selenium chemistry ;)

@vdvideocity - 2023-06-26

Beautiful blue colors. Thanks!

@jansenart0 - 2023-06-26

Hydrazine, lovely!

@Grateful.For.Everything - 2024-01-23

👏👏👏👏👏👏👏👏👏👏👏 really nice visuals!!!

@arnavtete7793 - 2023-06-26

thanks for this video!

@b33cux - 2023-06-27

This is ART!

@Spectrolite1 - 2023-06-26

Fantastic element, wow!

@williambradley611 - 2023-06-26

Love your vids

@echothebot - 2023-06-26

Oooh yes Nice Video, Thank you!

@mysock351C - 2023-06-26

I wonder how it smells outside? Selenium rectifiers had their own unique stench when they burned out. I can imagine it being perhaps a bit malodorous in a similar fashion if the fume hood doesn't have some sort of scrubber.

@Calilasseia - 2024-06-04

Organoselenium compounds are famous for their vomit inducing stenches. See Derek Lowe and his chemistry blog for more on this.

@dansheppard2965 - 2023-06-26

Great video, as ever, ChemicalForce!

@evilotis01 - 2023-06-26

7:53 me: wonders what'd happen w anhydrous hydrazine, but figures that'd prob be too difficult/dangerous
Feliks: i gotchu fam

@trishblackman7403 - 2023-07-12

Since I can’t blow shit up here at home….I’ll let you do it and sit back n watch the best stuff on tv!😊

@jhyland87 - 2023-06-27

Hey, off topic, but your English is getting much better. :-)

@aaronsmith8073 - 2023-06-26

Really enjoy your videos!