Berkelium in Berkeley (new) - Periodic Table of Videos

I mean you're dealing with an element there that hardly anyone ever gets to see or have anything to do with like does that excite you oh absolutely I mean it's uh it's quite surreal to to get to work with this and there's just uh so much uh chemistry to do and so many cool ideas not enough time in the day to get it done we're updating our video about element 97 which I call berum and Americans call berkum because it was discovered in the US city of Berkeley we're doing it in quite an unusual way because Brady was in Berkeley and he interviewed my former Nottingham colleague Professor Polly Arnold who is actually working with burkum or as she would say now being in America burkum they make it once every two years at one of the other National Labs and we spoke to the program manager of Department of energy who funds our big research group here um we had to basically write him a research proposal to tell him what we were going to do with half a milligram and we got it there's some really interesting questions about how you can do chemistry when you have such a tiny amount of an element less than a milligram if we wanted to get something like 5 milligrams we would probably spend about $300,000 when you realize you what a small amount you're normally going to get um you immediately think oh cripes we're never going to be able to make the confence we propos for this and then immediately you get together with all the people because there has to be a because it's so valuable a few of us have to get together and decide what we're going to do because every sample you get you plan you prepare you practice you rehearse with other suraga elements and then you recycle it right so you have to make something that you're going to be able to recycle so that your colleague your friend can use it again and again and again until its halflife means that there's none of it left basically bilian was first really isolated and studied in 1949 by the famous American chemist Glen seaborg and it was prepared using a cyclotron in the Lawrence Berkeley lab in Berkeley and they chose the name burkum because if you look at the periodic table verium comes underneath turum and their argument was that turum was named after itabe a town in Sweden so burkam would be named after Berkeley a town in California there's been surprising amount of work done on studying the chemistry of vum papers published in 19 70 starts describing the sort of apparatus they use and how they can use x-rays to study the structures of the compounds they make the compound in the 1970 paper consisted of a carbon hydrogen C5 H5 ring with the berium and in fact three of these Rings round it when you listen to PO Arnold talking she describes the organic part around the metal as Shrubbery Shrubbery is the word we use in English meaning bushes some rude people might describe my hair as Shrubbery but the idea is that if you surround an atom with organic lians organic groups this can allow you to do more sophisticated chem chemistry because one burum atom cannot easily react with another one because they're kept apart as Polly would say by the Shrubbery like they're in the little jail cells if you like but they're not like jail cells because they can move around a bit more like American footballers who are protected by all this heavy armor when they Bang into each other the Berkeley isotope that we get has a half life of 330 days so basically every week that we're sitting on it worrying about whether the reaction is going to work or not or reprocessing it we're counting how much we've lost you know we're all going oh we've only got three quarters of it left oh too much of it's turning into California we're going to have no Berk we don't want to contaminate our Spectra um and we we well we know that while it's constantly decomposing or turning into daughter products um not only are we giving out a radioactive dose to everybody but we're losing our chance to to have enough to grow crystals and to get beautiful data on concentrated samples so yeah it's stressful once the B helium has been made and we have a nice video showing the reactor at Oak Ridge where they make these elements this is the berkum sample he's getting out now we had less than a half a milligram of Berkeley remaining from our last production campaign Berkeley and SC a little over a 300 day halflife so it should be about half of it should still be remaining in this sample in the bottom of this glass bile it comes to a tip and there's a little bit of green solid material there it's a burum chloride and after it's been separated then what happens is that the people who want to study it have to write a proposal and there's a big competition all these different groups I want my billum and only a few of them get it and it's judged on the originality of the scientific ideas they put forward and it sounds as whatever Polly has proposed has been very successful but the paper hasn't yet been published so we don't know exactly what what she did I think it must be really exciting but they know that they've been successful in their application months beforehand and rather than sitting like you might do to wait for your Christmas presents they start practicing like mad because they choose a rare Earth element that has similar size and chemistry to the element they're studying in this case buium and they chose serium as the standin element if you like and they keep on practicing doing these experiments over and over again because they have to recycle the bikum you do an experiment and whether it's successful or not you get the berium back to do it again I understand this Berkelium sample arrived at Christmas it was a Christmas present it was a great Christmas present yeah yeah so we started working on it in January which was also extremely frustrating because because this is a national lab we have a winter shutdown that we respect very carefully what was it like when it arrived was it like a Christmas present were you all was there a buzz there there was a huge buzz and there's also um um a an incredibly uh frustrating moment where it arrives um protected from the people who are transporting it and the people who are receiving it so it comes into receiving and then the health and safety people the health physic assists have to collect it for us unpackaging bring it to us and we immediately put it into its Le leadline box while we get everything ready to do the reaction I think it's absolutely fascinating what they do and I believe although Polly didn't say this they can handle such small quantities of material because it's radioactive so even if you can't see the material you can use a counter to trace where it's got to in your [Music] apparatus the other thing is that once you've got crystals of this compound it the crystal only lasts for a short time because the energy of the pelium decaying shatters the crystal yeah the thing we have to really worry about is that um because the isotope we're working with 249 bleum is so radioactive um it will blow itself apart so when we grow a single Crystal that we would put on a defom to look at the molecular structure we've only got about 3 hours to measure that Crystal on the defect tometer before one of those um events has blown it apart I think that Brady saw the billum sample but it's really so small that I don't think any of people would get excited by this tiny Speck of material which is probably smaller than the specks of dirt on my table um it was tough at the beginning we were pretty new here as as a research group in Berkeley as well when it first came um so one of my people who was working with it she normally when you start working with transuranics anything beyond uranium you would practice on the first one neptunium and then plutonium um for which we have a fair amount of they're still rare and precious um but for her this was the the first trans ranic she worked with was Berkeley which is quite quite incredible given that there's probably only about a hundred maybe a couple of hundred people in the world that have ever seen work clear so quite an opportunity the really important question is why on Earth should people want to study it and it's not just to show how clever they are as chemists though they are pretty clever to do these experiments but it is to try and understand the behavior of the electrons around these atoms and these heavy elements like berium like californium are good analoges of the behavior of The Rare Earth elements that above them in the periodic table and the reason why they are important is because their behavior is more extreme than those of the rare Earths and so if you develop a theory to explain the behavior of the actinides these heavy elements then that theory will be much better at explaining the behavior of The Rare Earth elements the lanthanides than if you developed your theory just on the lanides do people assume that by the time you get to that point in the bottom of the period table bottom row um they they always lose the same number of electrons but there were hints and suggestions from other work that we could lose one extra for Berkle and we were convinced that by putting some organic uh plates either side of it to make a sandwich we could capture and understand that um that more oxidized form uh really well and it worked brilliantly for that it was exactly what we were hoping to see it's more stable than we were expeced what sounds as if was one of the most exciting discoveries of um poly's group's work was that they have found a chemical way of separating californium from berkele the reason why that's important is because normally you have a complicated procedure with resins and so on and according to what Polly said if I understood her correctly when they do a bit of chemistry they get a beautiful purple solution the colors of these heavy elements can often be very beautiful and they got purple solution and a precipitate of californium and they're going to do a whole lot of chemistry with the californium afterwards the californium has a much longer halflife so they have a bit of time to work out what they're going to do but what was very interesting to me is that the californium decays in a radioactive way different from pelium and so the radiation coming out of it is much more dangerous it's much stronger and therefore even though it lasts longer and therefore the atoms are decaying at a slower rate it appears to be much more radioactive these are not experiments that are done in every chemistry department but it's really important for the subject that somebody should be doing it we've got about a quarter of a milligram left that's really sad but we've got more coming thanks for watching if you enjoyed this video I'll put some links in the description to other videos we've made about these exotic elements including our visit to Oak Ridge and if you think you'd fancy a career in chemistry well why not study at the University of Nottingham where we make these videos I'll include a link about that also in the video description what

Channel: Periodic Videos

Views: 129,606

Keywords: periodic, videos, chemistry

Id: 7p1D9C1qkZY

Length: 13min 59sec (839 seconds)

Published: Wed Dec 06 2023