2:39 Part of my current PhD research is investigating the combustion aspects of a couple borohydrides, including LiBH4. It's currently not well understood exactly what is happening when LiBH4 burns (thus the research), but here is my theory. It is well known from the literature that LiBH4 decomposes to LiH, B, and H2 at low heating rates. Upon further heating, LiH decomposes and free Li atoms are released. Lithium has a low boiling point and a high vapor pressure, so many Li atoms make their way into the flame zone and react, giving us that beautiful red flame. Boron has a very high boiling point and low vapor pressure, making it difficult to burn in a diffusion flame, even without an oxide layer that is present on most boron particles (the boron oxide layer is why boron is notoriously difficult to burn quickly and efficiently). The flame from LiBH4 powder burning in air is a diffusion flame that is heating the powder relatively slowly, thus why we see only the Li burning and not the B. How LiBH4 reacts under rapid heating is not well understood. There is a theory (DOI:10.1021/cm100536a) that B2H6 is formed when LiBH4 decomposes. When heating rate is slow, the diborane then reacts with additional molten LiBH4 to form a Li2B12H12 intermediate species, which eventually decomposes further to LiH, B, and H2. However, under rapid heating, like when pure liquid oxygen is poured on the burning powder, the B2H6 does not have time to react with the molten LiBH4 and instead escapes the melt as a gas where it burns to HBO2 and B2O3, with the intermediate species BO2 giving off the green color! Side note on the colors: the red color from the Li is one wavelength; 671nm. So it is "pure" red. The green from BO2 comes from resonance lines in the 500-580nm range, so it's actually a mix of blue-green, green, and yellow-green. The strongest resonance line is at 546nm, which is the apple green that we see.
@@nigeldepledge3790 Hydrogen flames are nearly invisible, giving only a very faint blue color due to the presence of OH radicals. A great example of this is the Space Shuttle Main Engine, which used liquid hydrogen and oxygen as propellants. A slight blue tint to the flame is noticeable, but the nozzle exhaust is transparent enough to see right up into the engine as it is running.
I have asked before but I will keep asking! Please show us your lab, your safety procedures, your clean ups after some of these experiments, and we want to see you more. We all come to this channel because we like you and appreciate your time and effort into this videos. A lot of us are chemistry and science geeks plus your content is always interesting to watch. Thanks again for another interesting video look forward to another one. Also your content gets better and better every episode I remember when you did not have the high speed slowmo shots . Keep up the good work!
I used to work with tert-Butyllithium (BuLi), but in 90L cylinders. We had to suit up in shielded fire-protective gear, very sensitive and dangerous material.
We see it in our town in tractor trailer loads . It all goes to Orange TX. I've been in the refinery that uses it . Their safety procedures for receiving it are nuts.
volume is critical, there is a world of difference between what is needed to handle lab quantities safely and industrial quantities…. even then in the lab you try an minimise the quantities you have in the a actual lab to what you need on a day to day basis. its something i keep having to remind makerspaces about… you bigger bottles are cheaper per l, but the enhanced safety it needs will exceed the bulk savings
3:10 Lithium is much more electropositive than boron, which means that it will combust more easily with less oxygen - hence the formation of lithium boroxide when lithium borohydride burns. If on the other hand you add some liquid oxygen, then there's enough oxygen to make the combustion color of the boron overpower the combustion color of the lithium.
my thoughts also. It has something to do with Lithium being the primary oxidized element in atmospheric conditions and Boron becomes more actively oxidized at higher concentrations.
I really do not think one needs to go to such lengths to explain it. In order for a substance to color flame, it must be in the vapor phase. Melting point of lithium: 180C Melting point of Boron: 2000C It really is likely that simple.
no it is the hydrogen that's burning in both cases. because the oxidation state of H changes from -1 to +1. Li and B are in their respective oxidation states of +1 and +3 all the time. I think the colour is due to the temp of the flame in low temp burning the lithium was able undergo electronic transition emitting its characteristic color but in high temp burning in Liquid O boron typical green color was prominent because of volatility
"It's impossible to damage the bottle with tert-butyllithium during transportation and delivery." That just means you're not trying hard enough. Sometimes the multiple layers of packaging seemed a bit ridiculous, when I was doing organometallic work. Two layers of stiff cardboard, padded with vermiculite, etc., seemed overkill when the product in question was a small plastic baggie of nearly-indestructible rubber septa.
To me this indeed looked just like a particle effect I made quite recently in Niagara wich is Unreal Engines particle effect system and wich is capable of making some really cool shit regarding particle effect stuff! The difference is the effect I made was green but I can easily make it any color i want. Its however even cooler to see such phenomenons irl and not just simulated. Also this demo shows just how reactive tert butyl tithium is. First time I heard of this stuff was from a video from USCSB about a girl who got burned to death while working with this stuff alone in a lab and without proper fire resistant lab clothing. Scary stuff for sure!
The liquid chlorine volcano at the end was so cool! Not related to this video, but do you have the equipment needed to work with elemental fluorine? I’m almost surprised I haven’t seen it featured in any of your videos yet, unless I missed one!
No, but I have the opportunity to try to filming fluorine in a special laboratory at the factory where they work with pure fluorine. But this idea will be very expensive and I’m not ready to afford it yet with so many views 🥲
Yikes! That stuff is gnarly, but it would be a fascinating video. Is that a fluorine production facility or are they making interesting fluoro chemicals there? Thank you kindly for your fascinating videos....cheers!
Your videos always make my day and help to relax. I'd love to see you making a long compliation video of all these colorfull reactions with sooth ambient music, so we can watch them before sleep :D
The LiBH4 burning red is due to Li, but the green is because the O2 is attacking the B more dominantly than Li or H. Green is a characteristic color for B flame tests, similar to how red is for Li, lilac is for K, and a yellow-orange indicates Na.
Yes!! ❤❤it's like you heard my request that I didn't even post, but had in my heart❤ To attempt to answer your question about LiBH4 and oxygen turning green, I believe it has to do with the electron jumping further down, or further up then down (?) But nonetheless, it's awesome that you found that. My hunch is you just showed why the Strontium based laser presents as green.
That is one excellent collection of camera shots! Your next mission, should you choose to accept it ... replicate this with trimethylaluminium or one of the dialkyl zincs. For those unfamiliar with these particular pyrophoric flamethrowers, they make tert-butyllithium look tame. Straight dimethylzinc is an accident waiting to happen except in the hands of a VERY skilled chemist, and even then, a LOT of precautions need to be taken. If that reagent cuts loose in an uncontrolled fashion, mayhem on an industrial scale ensues. But, the compounds I've just mentioned produce some interesting flame colours of their own, and would probably be spectacular to watch in liquid oxygen. Provided this can be done without lethal shrapnel and flaming debris of course, which is ALWAYS a hazard to be aware of with this pair of organometallics. A less explosive, but dangerously toxic one, is dimethylcadmium. Though that again is a choice for bunker chemistry. Far rarer are actinide organometallics, though I suspect no one outside a national security institution will ever be able to perform even simple experiments with those. I'm also wondering what would happen with organometallic caesium compounds. Which again probably comes under the heading of bunker chemistry. Or, for that matter, various methyl derivatives of various transition metals. Though generating hexavalent chromium in any quantity is, er, not advisable for the unskilled. Though of course, even this collection of nightmare experiments pales into insignificance once dioxygen difluoride or chlorine trifluoride are part of your collection of reagents. Oddly enough, Derek Lowe has several interesting accounts of vicious organometallics, along with FOOF and ClF3 on his chemistry blog. Delivered in his own inimitable style. Recommended reading for those who want to see hideously dangerous chemistry sprinkled with fun metaphors.
I've already filmed studio material with trimethylaluminum and now I’m waiting for the opportunity to conduct experiments with it. ibb.co/jrZw8By But first just open this can without burning the laboratory and the entire building :D
When we were 11, maybe 12 - studying the reactions of the alkali metals in science class, we were all desperate to see what potassium would do (since we were allowed to react sodium in person and it was crazy). We could find one or two super low-resolution video and microblocked-to-hell videos of it. People with access to this channel and in general, the insane number of videos on RU-vid are just so lucky.
My guess regarding the colors observed during the combustion of lithium borohydride: During combustion in air, only lithium is vaporized, and the lithium emission is in the red range. By adding liquid oxygen, the boron is also vaporized, and boron has a green emission. The boron emission then appears to be more intense than the lithium emission.
You just keep making magic eh? What wonderful reactions with compounds I would never see otw! The colours!! Just awesome! You ever try using Ink (replacement) syringes? I think they will fire better than real syringes and have very similar twist-off-style (so you could just twist off the sharp one, and twist on the one for ink). I think the materials are also similar, but dunno for sure.
Magical. Chemistry in slo-mo and macro. Imagine, if there is no other technological advanced life, these extreme reactions are only possible here, on Earth.
I'm sticking with, you've gotta do a video with chlorine trifluoride at some point. You handle absurdly dangerous reagents like they're nothing special as you literally demonstrate the reactions that make them absurdly dangerous. It's a talent I've never seen from another youtuber, and as such, I think you're uniquely qualified to handle the mythical chemical that is chlorine trifluoride! Bonus points if you can show its reaction with asbestos, but since asbestos is dangerous for a very different reason, I imagine such a demonstration is kinda not feasible (since asbestos isn't just handled in a fume hood, or even an inert atmosphere, but rather more like a super dangerous virus, which is its own set of restrictions)
I'm convinced that he lives somewhere in a gigantic Sigma-Aldrich warehouse, sneaking around, making videos and sustaining himself on nothing but synthesized organics
I guess that boron ionizes at higher temperatures than lithium, therefore its green color applies more when oxygen is added. Also lithium is more volatile, so that it resides outside of green flame.
The lithium borohydride showed the green of boron once oxygen was added. Perhaps the red of the lithium oxidizing is less bright than the boron oxidizing, so we see the green, preferentially. A spectroscopic analysis through the reaction would be able to confirm whether both colours arw present and the ratio of their relative brightness.
Liquid O2? No wonder it takes so long to get through to their customer-services!!! 😛 Love this channel thanks ~ChemicalForce... You've got me trying to work out energy-levels thanks.! Of course it was the pentane burning yellow.! 🙂 Cool lithium blue!! Thanks! 😀 x 10^6
may be boron flame is brighter, but boron itself is less volatile, when burned in air and we don't see it. But when burned in the excess of oxygen (in LO2)...
A video about other pyrophoric organometallic liquids such as dimethylzinc or trimethylaluminum would certainly be interesting. I don't know if it was here, but the reaction of one of the strongest bases tert-butyllithium with the strongest acid fluoroantimonic acid would certainly be interesting. 
Instead of the Li being ionized, creating the red flame, when excess O2 is added the Li would be less likely to ionize (forming LiOH/Li2O (and LiBO4?)). The B is obviously ionizing in preference to the Li after O2 is added producing the green emission which could be from oxidized BOx complexes volatilizing.
I think liquid oxygen makes it burn hotter so that more boron gets introduced into the flame. Since our eyes are more susceptible to green than to red it's likely that more boron color will drown out the red from the lithium.
Liquid oxygen poured onto charcoal makes an excellent blasting agent - probably could crush up barbecue briquettes, pour them in the blast hole, add LOX and an initiator and Bob's your uncle!
I would guess boron is involved in the green color of burning lithium borohydride. Perhaps unless LOX is added to the mix, not enough boron is volatilized to color the flame.
You produce such impressive contents with beautiful flames, but can you upload an HDR version? RU-vid should support HDR, and the flames do need a high dynamic range, which you can enjoy with your eyes, but not us viewing it through the screen...
Unfortunately my camera only records 8 bit 4:2:0. My high speed camera can do this, but its buffer is only five seconds. I hope that in the near future I'll be able to update my camera and I'll manage to record 4:2:2 10 bit, then I'll be able to add HDR video. Thank you very much for the donation!
t-BuLi is the stuff of nightmares. The day when we can use something that isn't an extremely reactive alkali metal bonded to an extremely reactive alkane group in its place on a general level will be a momentous one lol
The borohydrate color change is probably due to the higher O2 concentration causing the reaction to proceed more energetically, and the higher temperature causing higher energy photons to be released.
The color change with the borohydride: is it possible that adding the liquid oxygen resulted in further oxidation of the combustion product? The temperature difference could also be a factor, but usually higher temperatures result in shorter wavelength spectral lines becoming dominant.
Highly oxygenated boron ? Lithium would burn easier and give the red flame where additional oxygen would break the lithium boron bond and allow it to burn I assume ?
You NEED a spectrometer. I have to see the spectrum of burning S with burning CO!! They're very cheap to get and you can use the free theremino software to analyze.
Hi! Since there is tert-Butyllithium, is there also tert-Butylrubidium or tert-Butylcesium; and will they be much more reactive than tert-Butyllithium?
