Elemental rubidium has a strong reducing character. When heating the rubidium within a quartz tube (silicon dioxide) to a certain temperature, amorphous silicon is formed as a thin layer causing the appearance of the brownish mirror. This is why the top of the ampoule (coldest part) stays clear.
@@takeiteasyashwin701 You can have a look at electronegativities (EN) which basically describes the tendency of an atom to attract electrons in (covalent) bonds. The higher the EN the higher the oxidation strength. Fluorine is a good example which reaches noble gas configuration when receiving an additional electron. Rb on the other hand has a low EN and tends to pass his single valence electron to Si in this case to rech noble gas electronic configuration. P.S. as a rule of thumb the EN within the periodic table increases from the bottom left to the top right for main group elements.
I have another theory, the color reminds me of NO2, witch has his color because of his unpaired electron, so maybe the gaseous rubidium radicals behave like NO2 while reflecting light?
@@eduardoGentile720 In a long comment I wrote about dome of the possibilities, I considered the possibilty that there might be a tiny amount of N2 left in the tube reacting to form unstable compounds with or because of the rubidium, maybe even actually NO2. I doubt there's actually NO2, but maybe something else with actual nitrogen could produce a similar color. (Note that Rb3N is unstable, but Li3N3 is stable.)
Amazing how it doesn't take oxygen to "oxidise" something. Oxidation is just a loss of electrons. Chlorine loves snatching electrons. Electrophilic nasty. Friggin love chemistry and it's about time we get a channel devoted to extreme reactions and such. Thanks for the efforts ChemicalForce and sweet camera quality, angles, lighting and especially sound.
Ever checked out ExplosionsandFire's channel? It's all the extreme chemistry you can handle without all that expensive safety equipment getting in the way
Or rubidium oxide yielded by the latter process, gold similarly produces a red vapour when heated to ignition just as it does when gold oxide is added to glass resulting in a suspension of gold oxide particles in glass producing a cranberry red stain. Though I believe gold itself added as a very fine powder to a glass mix may also yield the same result.
If it were the gas, then it would probably also fill the very top part of the ampule, which is clear if you look back at the clip. Most likely the color is coming from a thin film on the sides of the ampule.
Problem was if it was in a sealed ampoule. You can see microfractures in the ampoule when the metal condenses on the side of the glass it's sticks to the small cracks
It’s so good to see exotic elements and their compounds and reactions. You’re answering a lot of those “I wonder what would happen if you added X to Y questions “ thanks a heap
First of all, thanks for including chemical reactions with ozone and consider your viewers replies, that was very kind. It's been a lifetime waiting to see footages like this. Your videos are very valuable for amateur chemist and enthusiasts and also for professionals, you are doing an amazing work. 👍👍👍
4 года назад+6
I have a PhD in synthesis and I wouldn't have the balls to perform half the experiments on this channel. Very entertaining, stay safe bro. The little pop-up text with the reagents always gets and audible reaction out of me.
My new favourite chemical channel. I don't know where you live or who you are but it's impressive to see what type of rare chemicals you are able to get hold of. I get the distinct impression that you are quite the genius in the lab. Lastly, who doesen't like explosions, smoke and fire? =)
Obtaining Cesium and Rubidium Alums From Potassium Aluminum Suphate Years ago I was examining and older book with a title something like "Chemistry of the Rarer Elements". It would be about 100 years old now. It had a procedure where cesium and rubidium alums were obtained from potassium alum by fractional crystalization. The student would start with a kilo or so of potassium alum. They would dissolve it in water and evaporate it until it began to crystalize out. The crystals of alum were filtered off and redissolved. The process was repeated several times. Eventually less soluble alum crystals were obtained. These could be resolved into two salts, the really less soluble cesium alum and the less soluble rubidium alum. In potassium salts there are small amounts of the corresponding rubidium and cesium salts. The method exploits this property.
Your videos are way scarier than horror movies. Every few seconds I'm like OMG NOOOONONONO DON'T DO THAT NEVER DO THAT!! In this case it was boiling something in a sealed ampule, holy moly. I know it's under low pressure on the inside but every chemistry instinct in me is screaming. You've got a real death wish, dude, and as somebody who actually does not scare easily, I appreciate your sacrifice.
Beautiful videos. Boiling rubidium. Wow. Wonderful and incredible to watch all the strange elements and sometimes even stranger reactions. I am an element and chemistry nerd and could so far only imagine these things. Now I can at least virtually see them. Thank you.
17:50 y'know, after the liquid chlorine i thought for a moment you might be the one person on RUclips who'd actually be crazy enough to complete the halogen series and react the rubidium with fluorine. i'm glad to see i was wrong, though -- i like this channel and i don't want to see you blow yourself up :D
17:24 I think the alkaline elements usually present in the glass, sodium and potassium, are being replaced with rubidium. The absorption spectrum of the glass is then changed maybe due to the rubidium atom being way bigger than sodium and changing the structure.
The brownish color is obviously the color of the oxide or a form of the monoxide. You to see fractures in the ampoule especially when the metal condenses it tends to find the smallest spaces to stick to
My guess is that if the color doesn't go away when you cool it down, then it's reacting with the side of the ampule to form Rb2O and Rb4Si or maybe Rb4SiO4 and Rb4Si or some such. If it does go away, then it's probably reacting either with some gas like maybe N2 left in the tube or else impurities in the glass, and producing unstable compounds like maybe Rb3N. Full explanation below: I see people saying the color is either a reaction with the SiO2 ampule, or else is the color of the rubidium gas. It's also possible that there is a small amount of some other gas like maybe N2 left in the ampule that can react with rubidium at high temperature. I'll consider some evidence for and against these, but I don't have all the data about what happened, so you'll have to interpret what really happened base on a bit more than that video clip. A criticism against the latter idea that it's just rubidium gas is that you don't see that color when it first stars vaporizing. Maybe the gas pressure is just too low to see at lower temperatures. Alternatively, it could be that heating it causes a change like ionization, but I don't think it was hot enough for ionization and I don't what other reaction to heat would change the color. According to a USGS paper from 1995: " The heat capacity of gaseous cesium at constant pressure is 20.78 J mol^-1 K^-1 from it's boiling point at 947.96K to 1100K, then goes up to 20.79 for 1200K and 1300K and then rises further to 20.81, 20.84, 20.88, 20.95, and 21.04 for temperatures in 100K increments above that (1400K to 1800K). The heat capacity of gaseous potassium at constant pressure is given as 20.79 J mol^-1 K^-1 from it's boiling point at 1039.5K up to 1400K. It then goes up to 20.80, 20.81, 20.84, and 20.87 for 1500-1800K. Theoretical considerations show that all monatomic ideal gasses should have a heat capacity at constant pressure of 20.79 J mol^-1 K^-1. The lower number of 20.78 for cesium just above it's boiling point may be due to some kind of residual forces between atoms making not behave like a real gas (though I think it would have to be a repulsive force to make the heat capacity go down) or maybe it's just in error. Inspection of the tables for other elements in the paper shows that the later rise in heat capacity above 20.79 J mol^-1 K^-1 for gaseous metals happens at higher temperatures for more electronegative metals and and lower temperatures for less electronegative metals, which means that it is almost certainly due to some of the thermal energy going into ionizing atoms or otherwise exciting their electrons, i.e., the beginning of the transition to plasma. For some reason, the paper doesn't have this info for rubidium, but it's electronegativity is between that of cesium and that of potassium, so it must start significantly ionizing at a temperature between the 1300K-1400K of cesium and the 1400-1500K of potassium. According to the same paper, pure quartz doesn't melt until about 1700K, so it might be possible to heat the ampule up that hot, but if you did heat it to above 1300K it would be glowing orange, which it obviously wasn't in the upper part of the tube. Maybe ionization affects the color noticably before they change the heat capacity by ~0.01 J mol^-1 K^-1, though. As for chemical reactions, the reaction with SiO2 would be either: (SiO2) + 2(Rb) > (SiO) + (Rb2O) or (SiO2) + 4(Rb) > Si + 2(Rb2O) SiO is not particularly stable and disproportionates into Si and SiO2 if held for a few hours between 400°C and 800°C, but I don't see how either Si or SiO could steal back oxygens from the Rb2O as it cooled down, so I think this reaction would not be reversed and the color would remain. There might be so little Rb2O, SiO, and Si that they could somehow both dissolve in the excess rubidium unless you continued the reaction for a very long time, though, so the color might still go away. My only problem with this is that I think Rb2O and SiO are both black and Si is silvery or grey to black, so it's slightly weird that they would make a brown color. However, you already showed in the video that rubidium forms a silicide, and I'm pretty confidant it can form silicates. It might also react with impurities in the glass to form borates or borides or some such. It's quite possible that some of these other compounds could explain why it's brown rather than black. If there is gas like N2, or if there are other impurities in the walls of the ampule, then maybe it could react with those to form compounds that break down either immediately or when cooled. For example, Rb3N is not known as a stable compound, but Li3N apparently is, so maybe high temperature rubidium gas can also partially reduce nitrogen, and the unstable results can interact with light to cause the color before they fall apart/the nitrogen reoxidizes. If there is also some O2 in the tube, then it should be able to irreversibly react to form Rb2O just like if it stoll it from the glass, but maybe it could also catalyze the formation of nitrogen oxides like NO2 by pre-reducing the nitrogen. All that seems a bit wild, though, and, more importantly there can't be a gas that's brown, at least not one lighter than Rb gas, unless it stops being brown very fast when it cools down, because the very top section of the ampule is clear and not brown at all. Most likely the brown color is a liquid or solid coating on the side of the ampule and not a gas. I doubt that rubidium gas would cool down much as it convected to the top, anyway, so that also mostly kills the ionization idea.
Wow, I thought rubidium would react vigorously with liquid oxygen but instead it just solidified quickly (which makes sense being at below 90 kelvin). I guess like with all reactive metals you reacted with LO₂ it needs to be ignited in air first then exposed to the LO₂ for it to react. This video was so useful as taught me much! :)
I love your channel man keep up the good work! I like that you are original with your content and showcase things I typically wouldn't have even thought of.
My best guess for the color at the end would be gaseous Rb. Not sure, but I do know that other alkali metals are strongly colored in the gas phase (Potassium comes to mind with its vibrant blue/green color when gaseous)
Really great close-up photography and slow-motion capture in this video. Your techniques have truly improved! Thank you for the entertaining and sometimes surprising chemical reactions of this element that most of us will never see in person.
The actual reason is quite complicated, but as the atomic number increases, the electrons gain more freedom to move through the different layers, especially when they are excited. The metallic cesium is gold-colored in the room temperature, but rubidium is still colorless (metallic). As its atoms (which are in the 5th period) receive energy, the electrons move across the layers and imitate the behavior of the elections of the atoms in the 6th period of the periodic table (such as gold).
No, electrons in different atoms, which happen to have the same principal quantum numbers (and thus are in the same energy shell or "layer" as you put it) will almost always have vastly different spectroscopic properties and ionization energies. The whole reason gold has a golden colour is because of relativistic expansion of its 5d and contraction of its 6s orbitals, which allows for lower frequencies of light than usual (in this case blue-violet visible light in stead of only UV-light) to excite an electron between those orbitals. If you really want to know why, the only option is to buy some some good books on the relativistic Shroedinger equation and solving it for computational quantum chemistry (because solving it for systems with as many electrons as a gold atom is not going to happen by hand). There really is no simple way to put it, without lying to some extent. The commonly quoted reasoning of "the atom is so large and heavy that the electrons would need to move faster than the speed of light to orbit around it" is obviously wrong since electrons don't orbit around atoms, nor do they even move along any sort of continuous path. Yes, it is true that the electron's velocity is so great that things like relativistic length contraction and increased effective electron mass becomes important in gold's orbitals (with the latter having a particularly large effect on the outer orbital's energy level), but the reason why isn't easy to quantitatively explain in a satisfactory manner. As for Caesium, relativistic effects really aren't important in determining its colour. Here, it's simply a combination of its lone outer electron being even better shielded from the atomic nucleus, the Cs+ ion being more polarizable, and that the valence orbital is physically further from the nucleus, that all result in Cs having a plasmon excitation frequency (and thus energy) much lower than that of Rb, dipping into the visible violet range. Cs thus appears yellowish by reflected light, because it simply doesn't act like a shiny, reflecting metal for violet (and higher energy) light.
1:04 he said its under no pressure since its packed under vacuum also at the critical point the gas phase is as dense as the liquid phase so you cannot distinguish between a liquid and gaseous layer but you can clearly distinguish them in the image at 17:31 hence its not at its critical point yet furthermore you can see the brown color on the liquid rubidium when the ampule is broken i wonder if the brown color is reversible if not my bet is on the rubidium being oxidized by the SiO2 from the glass PS: i looked up the critical point of rubidium which sits at around 1800°C and 16 MPa i doubt the vessel would withstand that
The brown color when Rubidium is heated in the ampule is ionized rubidium vapor, similarly to when you add rubidium to liquid ammonia in large amounts.
Among the impurities in the brine recovery process is trace potassium in the ampoule when heated the potassium under low pressure will give a dark to light brown color and at Higher concentrations a change in coloration from a pink color and when cool goes back in solution
Very impressive. You don’t see much done with rubidium on RUclips. I have learned that rubidium cannot coexist peacefully with glass in its watch glass state.
If you want to open the ampule try scoring it, a piece of quartz crystal will work for that. After it's been scored more than 50% of the diameter where you want it to separate. Heat the edge of the crack with a butane torch. Hopefully that makes sense.
I think the brown color in the heated ampoule is just a high enough concentration of rubidium vapor that it's visible. Potassium vapor is green, so the same process done to an ampoule of potassium should produce a green rather than brown color.
My best guess is the bronze color you upon heating the ampoule is supercritical rubidium. Just before the triple point for rubidium to turn from liquid to gas and instantly back forming a pressurized vapour of rubidium.
(sorry for my english) It's One of The best video on your channel ! By the way, can you make a video with reactions with solutions of bromine, flammable gases, metals etc in for example acetone, ethanol, molten non metals For example reaction of bromine solution of H2S and cesium. Or reaction of liquid oxygen/ ozone with carbon disulfide solution of P4 More ideas : - liquid chlorine+ molten iron - titanium+ molten selenium -reactions with CSe2 - reactions with N2O3 or P2O3 - reactions with SiF4
Hi, being a chemist myself, I love your channel. But to be honest, I am concerned about your safety. Please extend safety equipment! First suggestion would be an additional shield between you and the place of reaction. Second, a groove, by which you can channel stuff towards the place of reaction, while keeping distace. Can I donate for the specific purpose of increasing your safety equipment?
Hi, mate! Most of the reactions are filmed with a macrolense, so that is what probably creates the impression of me working with bigger and thus more dangerous amounts of chemicals, which makes the audience anxious, but, in reality, that's not how the things are :) While performing dangerous reactions I'm protected quite well (I'm wearing a suit, gloves and a mask), which minimizes the chances of getting hurt. The things that really are on my mind for now are an enhanced air extraction system and new lighting equipment. Having the first one would allow me to make certain videos and having the second one would exclude any blinking in a frame thus making it more enjoyable to watch. So if you're really up to helping me with these, you can become a patron or a one-time donator on PayPal. You can find all the info in the description ;)
@@ChemicalForce Hi, thanks for the detailled answer. It is good, that you are considering carfully on this topic. Nevertheless, I would like to encourage you to considering more "remote" initiation of the reactions. You often have to approach quite closely with the pipet or spatula. If you would let liquids flow through a pre-installed groove or pipe, it would be safer. Same for solids, which could be added by a very long spatula that is attached to the surface by columns, but still can be turned. Even more sophisticated triggers using bowden control cables could be considered as well. I do not question your skills and expertise, please don''t get me wrong. Just asking you to remain humble with regards of your prediction skills on such reactions. Off-topic: More experiments with liquide ozone would be great. ☺ Stay safe!
Thank you very much for your donation!❤️ At least one reaction with liquid ozonated oxygen will be in the next video! Psst... tomorrow (or after tomorrow :D)
Wow, I don't remember the last time I saw a deflagrating spoon being used. Thank you for doing these videos! I have not-entirely-happy memories of trying to make "lithium sand" (granular lithium) in grad school by stirring lithium with strong heating under mineral oil in a nitrogen atmosphere. My best guess for what caused the resulting fire is that I was stirring it too strongly, which put the finely-dispersed molten lithium in contact with the nitrogen.
As I mentioned in the video, I used it as a surface to crush the ampoule on, so that you can see the clearest pink purple, free-from-other-ions colour of the flame in case rubidium lights up ;)
@@ChemicalForce ; But for the Zirconium one, all of the glass shards and fragments have already contaminated it with a lot of Sodium though, so I call bull$#!T! 8P It's quite simply an obvious flex, that you just had so much isotopically pure Zircalloy left over after constructing your nuclear reactor! uwu
@@BackYardScience2000 The ampule it came in was *definitely* not quartz. Would make the whole packaging process unnecessarily expensive for a product that already carries a substantial cost burden because of it.
I wonder did the rubidium, which was partially liquid, amalgamate with some of the zirconium foil, thereby inhibiting its reactivity. I'd have thought pure rubidium should have reacted explosively with the drops of water.
17:18 to answer your question, if I were to take a wild guess, that the strong heating of the rubidium caused some evaporation, and the vapor's overall structure caused those atoms to reflect that wavelength of visible light
...I have two questions....why doesn't the pressure rise when you heat the ampoule and crack? And wtf is happening to the watch glasses? Why are they shattering?
What gas was the ampoule filled with since oxygen is a bad idea lol? I have a feeling when heated it reacted with the Rubidium. Also gotta love the halogens and their breathtaking colors, and hazardous nature. Liquid chlorine and fluorine, and gaseous iodine and bromine are my personal favorite states for each element. Their solid phases would be next lol.
Well, but are You not afraid of extremaly hazardous of rubidium peroxide and superoxide, which may explode suddenly, for no apparent reason, and this is extremally insidious phenomenon?
Elemental rubidium has a strong reducing character. When heating the rubidium within a quartz tube (silicon dioxide) to a certain temperature, amorphous silicon is formed as a thin layer causing the appearance of the brownish mirror. This is why the top of the ampoule (coldest part) stays clear.
How to find oxidizing and reducing characters of the elements in periodic table
@@takeiteasyashwin701 You can have a look at electronegativities (EN) which basically describes the tendency of an atom to attract electrons in (covalent) bonds. The higher the EN the higher the oxidation strength. Fluorine is a good example which reaches noble gas configuration when receiving an additional electron. Rb on the other hand has a low EN and tends to pass his single valence electron to Si in this case to rech noble gas electronic configuration.
P.S. as a rule of thumb the EN within the periodic table increases from the bottom left to the top right for main group elements.
I have another theory, the color reminds me of NO2, witch has his color because of his unpaired electron, so maybe the gaseous rubidium radicals behave like NO2 while reflecting light?
The rubidium could also react with the amorphous silicon to form silicides, as shown in the video or maybe even silicates, which might be brown.
@@eduardoGentile720 In a long comment I wrote about dome of the possibilities, I considered the possibilty that there might be a tiny amount of N2 left in the tube reacting to form unstable compounds with or because of the rubidium, maybe even actually NO2. I doubt there's actually NO2, but maybe something else with actual nitrogen could produce a similar color. (Note that Rb3N is unstable, but Li3N3 is stable.)
Amazing how it doesn't take oxygen to "oxidise" something. Oxidation is just a loss of electrons. Chlorine loves snatching electrons. Electrophilic nasty. Friggin love chemistry and it's about time we get a channel devoted to extreme reactions and such. Thanks for the efforts ChemicalForce and sweet camera quality, angles, lighting and especially sound.
Ever checked out ExplosionsandFire's channel? It's all the extreme chemistry you can handle without all that expensive safety equipment getting in the way
It's especially funny because oxygen isn't even the strongest oxidizer, just the most well known (and is quite abundant)
I'd say the brown color is either rubidium gas, or more likely amorphous silicon getting freed from the glass as rubidium steals its oxygen.
The latter. All metal vapour is colorless
Or rubidium oxide yielded by the latter process, gold similarly produces a red vapour when heated to ignition just as it does when gold oxide is added to glass resulting in a suspension of gold oxide particles in glass producing a cranberry red stain. Though I believe gold itself added as a very fine powder to a glass mix may also yield the same result.
@@CATASTEROID934 Yes, this exists, it's simply called "Cranberry Glass", look it up on wikipedia^^
If it were the gas, then it would probably also fill the very top part of the ampule, which is clear if you look back at the clip. Most likely the color is coming from a thin film on the sides of the ampule.
Problem was if it was in a sealed ampoule. You can see microfractures in the ampoule when the metal condenses on the side of the glass it's sticks to the small cracks
It’s so good to see exotic elements and their compounds and reactions. You’re answering a lot of those “I wonder what would happen if you added X to Y questions “ thanks a heap
First of all, thanks for including chemical reactions with ozone and consider your viewers replies, that was very kind. It's been a lifetime waiting to see footages like this. Your videos are very valuable for amateur chemist and enthusiasts and also for professionals, you are doing an amazing work. 👍👍👍
I have a PhD in synthesis and I wouldn't have the balls to perform half the experiments on this channel.
Very entertaining, stay safe bro. The little pop-up text with the reagents always gets and audible reaction out of me.
My new favourite chemical channel. I don't know where you live or who you are but it's impressive to see what type of rare chemicals you are able to get hold of. I get the distinct impression that you are quite the genius in the lab. Lastly, who doesen't like explosions, smoke and fire? =)
Obtaining Cesium and Rubidium Alums From Potassium Aluminum Suphate
Years ago I was examining and older book with a title something like "Chemistry of the Rarer Elements". It would be about 100 years old now. It had a procedure where cesium and rubidium alums were obtained from potassium alum by fractional crystalization.
The student would start with a kilo or so of potassium alum. They would dissolve it in water and evaporate it until it began to crystalize out. The crystals of alum were filtered off and redissolved. The process was repeated several times. Eventually less soluble alum crystals were obtained. These could be resolved into two salts, the really less soluble cesium alum and the less soluble rubidium alum.
In potassium salts there are small amounts of the corresponding rubidium and cesium salts. The method exploits this property.
Your videos are way scarier than horror movies. Every few seconds I'm like OMG NOOOONONONO DON'T DO THAT NEVER DO THAT!! In this case it was boiling something in a sealed ampule, holy moly. I know it's under low pressure on the inside but every chemistry instinct in me is screaming. You've got a real death wish, dude, and as somebody who actually does not scare easily, I appreciate your sacrifice.
You spoiled us with this amazing compilation of super stunning reactions! The ozone had me on the edge of my seat... ❤️
Beautiful videos. Boiling rubidium. Wow. Wonderful and incredible to watch all the strange elements and sometimes even stranger reactions. I am an element and chemistry nerd and could so far only imagine these things. Now I can at least virtually see them. Thank you.
Glad you enjoyed it! Don't miss today's video about magic acid 😃
I want to thank you so much i cannot express in words. You listened to my request of rubidium.Thank u so much.Love you a lot.
17:50 y'know, after the liquid chlorine i thought for a moment you might be the one person on RUclips who'd actually be crazy enough to complete the halogen series and react the rubidium with fluorine. i'm glad to see i was wrong, though -- i like this channel and i don't want to see you blow yourself up :D
17:24 I think the alkaline elements usually present in the glass, sodium and potassium, are being replaced with rubidium. The absorption spectrum of the glass is then changed maybe due to the rubidium atom being way bigger than sodium and changing the structure.
probably unless it's a quartz ampoule then maybe rubidium vapor
Most likely! Great thought!
He uses quartz tubes.
BackYard Science 2000 I’m talking about the ampoule
The glass on calculator screen is hardened with potassium.
13:40 is really my favourite! The colours are really beautiful especially the deep dark purple one!
The brownish color is obviously the color of the oxide or a form of the monoxide. You to see fractures in the ampoule especially when the metal condenses it tends to find the smallest spaces to stick to
It is molecular rubidium (Rb2) in the vapor phase. This happens when Rb vapor cools down.
My guess is that if the color doesn't go away when you cool it down, then it's reacting with the side of the ampule to form Rb2O and Rb4Si or maybe Rb4SiO4 and Rb4Si or some such. If it does go away, then it's probably reacting either with some gas like maybe N2 left in the tube or else impurities in the glass, and producing unstable compounds like maybe Rb3N. Full explanation below:
I see people saying the color is either a reaction with the SiO2 ampule, or else is the color of the rubidium gas. It's also possible that there is a small amount of some other gas like maybe N2 left in the ampule that can react with rubidium at high temperature. I'll consider some evidence for and against these, but I don't have all the data about what happened, so you'll have to interpret what really happened base on a bit more than that video clip.
A criticism against the latter idea that it's just rubidium gas is that you don't see that color when it first stars vaporizing. Maybe the gas pressure is just too low to see at lower temperatures. Alternatively, it could be that heating it causes a change like ionization, but I don't think it was hot enough for ionization and I don't what other reaction to heat would change the color.
According to a USGS paper from 1995: "
The heat capacity of gaseous cesium at constant pressure is 20.78 J mol^-1 K^-1 from it's boiling point at 947.96K to 1100K, then goes up to 20.79 for 1200K and 1300K and then rises further to 20.81, 20.84, 20.88, 20.95, and 21.04 for temperatures in 100K increments above that (1400K to 1800K).
The heat capacity of gaseous potassium at constant pressure is given as 20.79 J mol^-1 K^-1 from it's boiling point at 1039.5K up to 1400K. It then goes up to 20.80, 20.81, 20.84, and 20.87 for 1500-1800K.
Theoretical considerations show that all monatomic ideal gasses should have a heat capacity at constant pressure of 20.79 J mol^-1 K^-1. The lower number of 20.78 for cesium just above it's boiling point may be due to some kind of residual forces between atoms making not behave like a real gas (though I think it would have to be a repulsive force to make the heat capacity go down) or maybe it's just in error. Inspection of the tables for other elements in the paper shows that the later rise in heat capacity above 20.79 J mol^-1 K^-1 for gaseous metals happens at higher temperatures for more electronegative metals and and lower temperatures for less electronegative metals, which means that it is almost certainly due to some of the thermal energy going into ionizing atoms or otherwise exciting their electrons, i.e., the beginning of the transition to plasma.
For some reason, the paper doesn't have this info for rubidium, but it's electronegativity is between that of cesium and that of potassium, so it must start significantly ionizing at a temperature between the 1300K-1400K of cesium and the 1400-1500K of potassium. According to the same paper, pure quartz doesn't melt until about 1700K, so it might be possible to heat the ampule up that hot, but if you did heat it to above 1300K it would be glowing orange, which it obviously wasn't in the upper part of the tube. Maybe ionization affects the color noticably before they change the heat capacity by ~0.01 J mol^-1 K^-1, though.
As for chemical reactions, the reaction with SiO2 would be either:
(SiO2) + 2(Rb) > (SiO) + (Rb2O)
or
(SiO2) + 4(Rb) > Si + 2(Rb2O)
SiO is not particularly stable and disproportionates into Si and SiO2 if held for a few hours between 400°C and 800°C, but I don't see how either Si or SiO could steal back oxygens from the Rb2O as it cooled down, so I think this reaction would not be reversed and the color would remain. There might be so little Rb2O, SiO, and Si that they could somehow both dissolve in the excess rubidium unless you continued the reaction for a very long time, though, so the color might still go away. My only problem with this is that I think Rb2O and SiO are both black and Si is silvery or grey to black, so it's slightly weird that they would make a brown color. However, you already showed in the video that rubidium forms a silicide, and I'm pretty confidant it can form silicates. It might also react with impurities in the glass to form borates or borides or some such. It's quite possible that some of these other compounds could explain why it's brown rather than black.
If there is gas like N2, or if there are other impurities in the walls of the ampule, then maybe it could react with those to form compounds that break down either immediately or when cooled. For example, Rb3N is not known as a stable compound, but Li3N apparently is, so maybe high temperature rubidium gas can also partially reduce nitrogen, and the unstable results can interact with light to cause the color before they fall apart/the nitrogen reoxidizes.
If there is also some O2 in the tube, then it should be able to irreversibly react to form Rb2O just like if it stoll it from the glass, but maybe it could also catalyze the formation of nitrogen oxides like NO2 by pre-reducing the nitrogen. All that seems a bit wild, though, and, more importantly there can't be a gas that's brown, at least not one lighter than Rb gas, unless it stops being brown very fast when it cools down, because the very top section of the ampule is clear and not brown at all. Most likely the brown color is a liquid or solid coating on the side of the ampule and not a gas. I doubt that rubidium gas would cool down much as it convected to the top, anyway, so that also mostly kills the ionization idea.
This is the best ever reaction video. The liquid gasses really made the difference! :)
The ozone liquid is just mesmerizing with its electric blue/violet color!😮
8:17 this is so cool! I never thought I would see something like this and I appreciate you showing it to us!
That's a huge knowledge i am getting from these videos visually... thanks
Wow, I thought rubidium would react vigorously with liquid oxygen but instead it just solidified quickly (which makes sense being at below 90 kelvin). I guess like with all reactive metals you reacted with LO₂ it needs to be ignited in air first then exposed to the LO₂ for it to react.
This video was so useful as taught me much! :)
I love your channel man keep up the good work! I like that you are original with your content and showcase things I typically wouldn't have even thought of.
My best guess for the color at the end would be gaseous Rb. Not sure, but I do know that other alkali metals are strongly colored in the gas phase (Potassium comes to mind with its vibrant blue/green color when gaseous)
This is amazing.I have been wanting to see this reaction for a long time very cool sir.
Finally, we got amazing content
Thank you for damaging things for us!
This is the best channel that i have ever seen 👍
Are you new to youtube??
cleaning up and quenching left overs like unreacted Rb and those spilled halogens will be a pain
Drown it in sodium thiosulfate solution. Halogens are nasty but at least they are easy to neutralise. Rb metal might cause cool little explosions :P
The oxinated Rb in that spoon looked like some junkies dream drug
Just ONE shot, ONCE, and you NEVER need any drugs again! XD
Those pictures were so cool!!! Keep up the good work
I'm so glad I found this channel, your videos are fantastic.
Really great close-up photography and slow-motion capture in this video. Your techniques have truly improved! Thank you for the entertaining and sometimes surprising chemical reactions of this element that most of us will never see in person.
1:35 You should try to get this wiping/microdroplets forming action on high speed and ultra magnified if possible. Amazing visuals on this one!!
The actual reason is quite complicated, but as the atomic number increases, the electrons gain more freedom to move through the different layers, especially when they are excited. The metallic cesium is gold-colored in the room temperature, but rubidium is still colorless (metallic). As its atoms (which are in the 5th period) receive energy, the electrons move across the layers and imitate the behavior of the elections of the atoms in the 6th period of the periodic table (such as gold).
No, electrons in different atoms, which happen to have the same principal quantum numbers (and thus are in the same energy shell or "layer" as you put it) will almost always have vastly different spectroscopic properties and ionization energies.
The whole reason gold has a golden colour is because of relativistic expansion of its 5d and contraction of its 6s orbitals, which allows for lower frequencies of light than usual (in this case blue-violet visible light in stead of only UV-light) to excite an electron between those orbitals.
If you really want to know why, the only option is to buy some some good books on the relativistic Shroedinger equation and solving it for computational quantum chemistry (because solving it for systems with as many electrons as a gold atom is not going to happen by hand). There really is no simple way to put it, without lying to some extent. The commonly quoted reasoning of "the atom is so large and heavy that the electrons would need to move faster than the speed of light to orbit around it" is obviously wrong since electrons don't orbit around atoms, nor do they even move along any sort of continuous path. Yes, it is true that the electron's velocity is so great that things like relativistic length contraction and increased effective electron mass becomes important in gold's orbitals (with the latter having a particularly large effect on the outer orbital's energy level), but the reason why isn't easy to quantitatively explain in a satisfactory manner.
As for Caesium, relativistic effects really aren't important in determining its colour. Here, it's simply a combination of its lone outer electron being even better shielded from the atomic nucleus, the Cs+ ion being more polarizable, and that the valence orbital is physically further from the nucleus, that all result in Cs having a plasmon excitation frequency (and thus energy) much lower than that of Rb, dipping into the visible violet range. Cs thus appears yellowish by reflected light, because it simply doesn't act like a shiny, reflecting metal for violet (and higher energy) light.
I like how, just as back vocals to the star of the video - rubidium, we can see liquid chlorine and ozone casually thrown about.
Hey, could you experiment with ozonides, formed by burning K, Rb and Cs in ozone? Thanks! Keep up the good work man!
17:31 are you pushing some electrons into higher orbitals
similar to the effect which makes cesium have a golden color?
I disagree. The material is past its boiling point, yet, the pressure keeps it close to condensation. Classical super-critical liquid.
Toy-joda I’m with you he said it was super pressurized earlier so the heat made it super critical
1:04 he said its under no pressure since its packed under vacuum
also at the critical point the gas phase is as dense as the liquid phase so you cannot distinguish between a liquid and gaseous layer
but you can clearly distinguish them in the image at 17:31
hence its not at its critical point yet
furthermore you can see the brown color on the liquid rubidium when the ampule is broken
i wonder if the brown color is reversible
if not my bet is on the rubidium being oxidized by the SiO2 from the glass
PS: i looked up the critical point of rubidium which sits at around 1800°C and 16 MPa
i doubt the vessel would withstand that
TheRolemodel1337 thanks man I have no idea
The brown color when Rubidium is heated in the ampule is ionized rubidium vapor, similarly to when you add rubidium to liquid ammonia in large amounts.
Ozone difluoride being a more stable compound then ozone itself. Would be an interesting reaction of cobalt fluoride and ozone
Among the impurities in the brine recovery process is trace potassium in the ampoule when heated the potassium under low pressure will give a dark to light brown color and at Higher concentrations a change in coloration from a pink color and when cool goes back in solution
Rb is probably reducing the silicon in the glass. Or maybe boron too since it's likely borosilicate glass.
Rubidium is that smart Asian kid that everyone thinks is going to win the Nobel prize for medicine but became a well-to-do vet
Brown color can happen as silicon reduced from glass by rubidium vapour
best channel I have ever come across...Keep the good work up.....Hope to see u with a lot of subscribers one day...Good luck brother
Very impressive. You don’t see much done with rubidium on RUclips. I have learned that rubidium cannot coexist peacefully with glass in its watch glass state.
The nano particles of Rb are so small that they interact with light in a way to change its colour appearance. Same concept at anodizing aluminum
If you want to open the ampule try scoring it, a piece of quartz crystal will work for that. After it's been scored more than 50% of the diameter where you want it to separate. Heat the edge of the crack with a butane torch. Hopefully that makes sense.
I'm aware about it, thanks. But I needed the showiest way of opening in :D
@@ChemicalForce Oh, that makes sense. I figured you probably knew already. Especially considering the amount of reactants you're dealing with.
Refluxing Rb! I have lived....
lol
You're welcome. 😉
ruclips.net/video/r1OU0FYH0W4/видео.html
Thanks so much for such great videos of such dangerous reactions. It's a wonder how you have not blown yourself up!
I think the brown color in the heated ampoule is just a high enough concentration of rubidium vapor that it's visible. Potassium vapor is green, so the same process done to an ampoule of potassium should produce a green rather than brown color.
Your videos are amazing!
Some really interesting colours in these experiments!
Amazing as allways! Cool mini smoke rings coming down at 5:54 on the left there
mini smoke no, big smoke
Who would thumbs down this video and Why? This was a great demonstration.
Nice one!! Especially all the reactions at the end👍🏼
My best guess is the bronze color you upon heating the ampoule is supercritical rubidium. Just before the triple point for rubidium to turn from liquid to gas and instantly back forming a pressurized vapour of rubidium.
(sorry for my english)
It's One of The best video on your channel ! By the way, can you make a video with reactions with solutions of bromine, flammable gases, metals etc in for example acetone, ethanol, molten non metals
For example reaction of bromine solution of H2S and cesium.
Or reaction of liquid oxygen/ ozone with carbon disulfide solution of P4
More ideas :
- liquid chlorine+ molten iron
- titanium+ molten selenium
-reactions with CSe2
- reactions with N2O3 or P2O3
- reactions with SiF4
Feliks, thanks for sharing so many reactions involving chemicals most of us don't have access to.
You could make piranha solution with oleum and 100%, or whatever your highest concentration h2o2 is. It’ll probably immediately explosively boil.
Can you please show more ozone reactions? Maybe in even higher concentrations?
Hi, being a chemist myself, I love your channel. But to be honest, I am concerned about your safety. Please extend safety equipment! First suggestion would be an additional shield between you and the place of reaction. Second, a groove, by which you can channel stuff towards the place of reaction, while keeping distace. Can I donate for the specific purpose of increasing your safety equipment?
Hi, mate! Most of the reactions are filmed with a macrolense, so that is what probably creates the impression of me working with bigger and thus more dangerous amounts of chemicals, which makes the audience anxious, but, in reality, that's not how the things are :) While performing dangerous reactions I'm protected quite well (I'm wearing a suit, gloves and a mask), which minimizes the chances of getting hurt. The things that really are on my mind for now are an enhanced air extraction system and new lighting equipment. Having the first one would allow me to make certain videos and having the second one would exclude any blinking in a frame thus making it more enjoyable to watch. So if you're really up to helping me with these, you can become a patron or a one-time donator on PayPal. You can find all the info in the description ;)
@@ChemicalForce Hi, thanks for the detailled answer. It is good, that you are considering carfully on this topic. Nevertheless, I would like to encourage you to considering more "remote" initiation of the reactions. You often have to approach quite closely with the pipet or spatula. If you would let liquids flow through a pre-installed groove or pipe, it would be safer. Same for solids, which could be added by a very long spatula that is attached to the surface by columns, but still can be turned. Even more sophisticated triggers using bowden control cables could be considered as well. I do not question your skills and expertise, please don''t get me wrong. Just asking you to remain humble with regards of your prediction skills on such reactions.
Off-topic: More experiments with liquide ozone would be great. ☺
Stay safe!
Thank you very much for your donation!❤️
At least one reaction with liquid ozonated oxygen will be in the next video!
Psst... tomorrow (or after tomorrow :D)
Love the lapel mic in the beard for the intro. Genius
Really nice seeing all those quite energetic reactions ! I'm thinkink the bronze-ish colour at the end is supercritical Rb vapour ?
Is that a rubidium argon complex... thing? Love your videos man!!!
Wow, I don't remember the last time I saw a deflagrating spoon being used. Thank you for doing these videos!
I have not-entirely-happy memories of trying to make "lithium sand" (granular lithium) in grad school by stirring lithium with strong heating under mineral oil in a nitrogen atmosphere. My best guess for what caused the resulting fire is that I was stirring it too strongly, which put the finely-dispersed molten lithium in contact with the nitrogen.
The Rb seems to reduce the SiO2 of the ampule glass to elemental silicon which could be brownish layer in the amorph state.
17:25 my guess is that more concentrated Rb vapor has color?
what's the reason for the zirconium and tantalum sheets? they didn't take any part in the Rb +H2O reaction, right?
As I mentioned in the video, I used it as a surface to crush the ampoule on, so that you can see the clearest pink purple, free-from-other-ions colour of the flame in case rubidium lights up ;)
@@ChemicalForce ; But for the Zirconium one, all of the glass shards and fragments have already contaminated it with a lot of Sodium though, so I call bull$#!T! 8P
It's quite simply an obvious flex, that you just had so much isotopically pure Zircalloy left over after constructing your nuclear reactor! uwu
@@mortlet5180 , he uses quartz tubes. Not borosilicate.
@@BackYardScience2000 The ampule it came in was *definitely* not quartz.
Would make the whole packaging process unnecessarily expensive for a product that already carries a substantial cost burden because of it.
This guy and the slow mo guys should do a collab video!
For a lot of chemicals, the cheapest vendor is AkScientific out of california - they usually deliver in 2 days
I appreciate how you have clipped the lavalier microphone to your beard.
I wonder if you can heat this ampule to such an extent that it would arrive in equilibrium where the triple point of Rubidium is
It forms a plasma in the glas tube and codes the glas with a thin layer of rubidium. I am just guessing here pls don t judge me if i am wrong.
Silicon dioxide in the ampoule undergoes reduction to brownish silicon monoxide assuming the ampoule is filled with inert gas like Argon.
now you could drop this rubidium into a superacid - HClO4, HSO3F or something
17:29 Rb metal reacts with the inert atmospher in the ampull ex. Nitrogen, Xenon, Argon ect.
Or maybe it reacts with the silicon dioxide, forming rubidium oxide and silicon, which you see as a brownish mirror.
I wonder did the rubidium, which was partially liquid, amalgamate with some of the zirconium foil, thereby inhibiting its reactivity. I'd have thought pure rubidium should have reacted explosively with the drops of water.
Is the brown coming from a reaction with the glass?
You're a wizard, sir. This channel is true magic :D
17:18 to answer your question, if I were to take a wild guess, that the strong heating of the rubidium caused some evaporation, and the vapor's overall structure caused those atoms to reflect that wavelength of visible light
"Rb vs liquid O2" is very interesting.
Reacting Rb with Teflon powder would be interesting.
toxic carcinogen
Mmm, carcinogenic and reactive C₂F₄!
...I have two questions....why doesn't the pressure rise when you heat the ampoule and crack? And wtf is happening to the watch glasses? Why are they shattering?
WOW. This footage is awesome. upload in 4k next time
Why didn't the ampoule break when it was being heated? Doesn't the pressure increase a lot when the Rb is boiled?
@9:53 you can see the vapours reacting before chemical contact
Thoroughly enjoyed that
What gas was the ampoule filled with since oxygen is a bad idea lol? I have a feeling when heated it reacted with the Rubidium. Also gotta love the halogens and their breathtaking colors, and hazardous nature. Liquid chlorine and fluorine, and gaseous iodine and bromine are my personal favorite states for each element. Their solid phases would be next lol.
What happenes if you Nitate it and add potassium pomegranate and possibly concentrated ammonium hydroxide?
Reaction with olium is superb
The bromide and rubidium was a fire work
Well, but are You not afraid of extremaly hazardous of rubidium peroxide and superoxide, which may explode suddenly, for no apparent reason, and this is extremally insidious phenomenon?
It's a myth!
7:32 RbO2 ? :/
Superoxide
Hey please react rubidium with concentrated hydrogen peroxide.
Maybe silicon from the glass ampoule, which is formed by reduction of silicon dioxide with rubidium?
So, um... What does rubidium do with elemental fluorine?
How did you cut the other one open? A hot wire?
It is the best channel in the world! Can you make a SiO (SiO2+Si=2SiO) please! becouse wiki have not any photos of SiO
rubidium oxide thermite? is it a thing? is it even possible? would it self ignite due to water in the atmosphere?
3:35 haha the accent makes you sound like you said "take a look at this shit"