Einsteinium: secrets of 99th element unlocked

Einsteinium is one of the cleverer-sounding elements you’ll see on your periodic table, but it’s a lot further down the list than something like carbon, or gold, or mercury. While carbon is number 6, gold is number 79, and mercury is number 80, einsteinium is the 99th element! It’s also radioactive, meaning it doesn’t stick around for long before it breaks down into something else. That makes it hard to study, and even though it was discovered in the 50s, we know very little about it. But this week, scientists at the Lawrence Berkeley National Laboratory managed to capture some in a molecular cage. Kit Chapman didn’t work on the study but he did write the book on the periodic table, called 'Superheavy', and he took Adam Murphy through the discovery...

Kit - Einsteinium doesn't exist on Earth. Anything beyond uranium, which is element 92 - and remember einsteinium is 99 - just doesn't exist on Earth. And usually these are made through nuclear reactions or particle accelerators, but einsteinium and fermium were actually first discovered from the remains of a thermonuclear bomb explosion. There was a bomb explosion in the 1950s in the Pacific - they were testing this world's first hydrogen bomb - and they actually ordered fighter planes to fly inside the cloud and gather up debris. And from those filters, we managed to find einsteinium and fermium

Adam - Looking at that, can you give us kind of the rundown of what they've done here at the Los Alamos lab?

Kit - Well, this is really impressive because there isn't very much einsteinium in the world. As I mentioned, it just doesn't exist on Earth, you have to make it. And so they managed to get 200 nanograms, which is a tiny, tiny amount. And they started to look at its properties. Now because it's radioactive, we haven't done many experiments on einsteinium. What they did was they took an einsteinium atom and they wrapped it in a sort of molecular cage, and they looked at it from that angle. And they began to do some X-ray tests on it, and from that they could actually study the bonds, and how it bonds with this... what we call a ligand, this cage it's in. And what it found was that it didn't follow the pattern they expected: it doesn't behave like the other actinides, some of the lighter actinides next to it, it starts to behave a little bit differently. And that's really interesting.

Adam - I understand that we don't have very much of it, but how do you determine that this thing exists and then know so little about it for so long?

Kit - The problem is making it. So there isn't any use for einsteinium in the world. There's no practical applications. Californium, which is a bit lighter - that's element 98, the next one along - that's really useful for the oil industry and for a host of other different applications. And so there's a reason to make it. There's a reactor in Oak Ridge, in Tennessee, and a reactor in Russia; and they can actually create these elements, they have the ability to do so. And when they're making californium, they're probably going to make a little bit of einsteinium as well because of the way they're doing it; essentially they nudge things up the periodic table. And so it's only... almost as a byproduct that you're actually producing einsteinium, and that's why we just don't have much of it. It's also only got a half-life of, I think, 275 days, which is incredibly short. It's not the shortest - some of the ones even bigger have half-lifes of minutes or seconds - but it's not very long at all, which means that it rapidly degrades. So you've got to be very quick in terms of the experiments you do,

Adam - As you were saying there, einsteinium doesn't have any practical applications. So why does it matter that we can do this with this now?

Kit - It's one of the building blocks of the universe! And the more knowledge we have about the universe and how it works, the more we can understand things. Just because einsteinium doesn't exist on Earth, it doesn't mean it doesn't exist in nature. You'll find it inside supernovae; you'll find it inside of neutron stars colliding. And so the more that we can understand about how these building blocks work, how they interact with things, how what we call relativistic effects affect the way that chemicals work... really gives us a clearer picture of how the universe is constructed. And that means potentially we have all kinds of applications in the future that we just can't think about yet.

Adam - What's the next frontier in this kind of research? What's the next big thing that's coming out?

工具——下一个大事件真的很难预测. We're hoping that it could be a new element. So if this stuff has gone over to Japan, and they've fired probably calcium into it - a very interesting isotope of calcium called calcium-48, which was used to create some other elements - then potentially we could have element 119. And if that's the case, then we have an entire new row of the periodic table starting, and that just opens up all kinds of possibilities.