Vorpal
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There's a relatively obscure controversy about the placement of lanthanum/lutetium and actinium/lawrencium that's been brewing for about three decades now. As it happens, the youtube channel Periodic Videos did a nice video on it:
It's a bit of a personal issue for Sir Martyn, because the news that their boxer shorts may be wrong would be quite troubling to anyone.
Anyway, I think this is pretty cool because before today, I didn't even realize it was possible for there to be controversy over where an element goes in the periodic table. Except perhaps hydrogen, but everyone already knows that hydrogen is the joker in the pack anyway. Both the IUPAC and wikipedia try to avoid the issue completely by drawing the periodic table like this:
On the left (groups 1-2) are the s-block elements, the transition metals (groups 3-12) constitute the d-block, and on the right are the p-block elements. On the bottom are the the f-block elements, of which there are two rows of 15. This is perhaps surprising, because the f orbital should have angular momentum l = 3, and so 2(2l+1) = 14 states, not 15. But actually, the electron configurations are a bit screwed up, e.g. Ac is [Rn]6d¹7s², Th is [Rn]6d²7s², and then Pa is [Rn]5f²6d¹7s². It makes this jump of first not filling up any of the 5f orbitals and then does two at once. So calling them 'f-block elements' shouldn't be taken completely literally in terms of the orbitals; perhaps it's not a big deal whether there are 14 or 15.
However, most periodic tables place La and Ac in that missing space, thus placing them with Group 3. The video says that according to this paper, it's actually Lu and Lr, the end the lanthanide/actinide block, that should go in Group 3. The paper itself doesn't seem to do that though, so I'm not sure what Prof. Poliakoff is talking about.
Perhaps he is agreeing with William Jensen, who says the paper supports his previous arguments that it is Lr should be placed in Group 3 rather than La. Notably, one of the authors of the paper, Matthias Schädel, says the paper supports Lr being put in the f-block, while the team leader behind the measurement, Tetsuya Sato, says that it doesn't provide enough evidence either way. (Cf. here) So it does seem a somewhat controversial topic after all.
I wonder if there are any chemistry-trained people here that could shed some light on this...
Side note: before the 1940s, Lu was placed with Group 3, so Jensen's position is basically that this was the correct grouping all along. Lawrencium wasn't discovered then, but is right below lutetium.
It's a bit of a personal issue for Sir Martyn, because the news that their boxer shorts may be wrong would be quite troubling to anyone.
Anyway, I think this is pretty cool because before today, I didn't even realize it was possible for there to be controversy over where an element goes in the periodic table. Except perhaps hydrogen, but everyone already knows that hydrogen is the joker in the pack anyway. Both the IUPAC and wikipedia try to avoid the issue completely by drawing the periodic table like this:
On the left (groups 1-2) are the s-block elements, the transition metals (groups 3-12) constitute the d-block, and on the right are the p-block elements. On the bottom are the the f-block elements, of which there are two rows of 15. This is perhaps surprising, because the f orbital should have angular momentum l = 3, and so 2(2l+1) = 14 states, not 15. But actually, the electron configurations are a bit screwed up, e.g. Ac is [Rn]6d¹7s², Th is [Rn]6d²7s², and then Pa is [Rn]5f²6d¹7s². It makes this jump of first not filling up any of the 5f orbitals and then does two at once. So calling them 'f-block elements' shouldn't be taken completely literally in terms of the orbitals; perhaps it's not a big deal whether there are 14 or 15.
However, most periodic tables place La and Ac in that missing space, thus placing them with Group 3. The video says that according to this paper, it's actually Lu and Lr, the end the lanthanide/actinide block, that should go in Group 3. The paper itself doesn't seem to do that though, so I'm not sure what Prof. Poliakoff is talking about.
Perhaps he is agreeing with William Jensen, who says the paper supports his previous arguments that it is Lr should be placed in Group 3 rather than La. Notably, one of the authors of the paper, Matthias Schädel, says the paper supports Lr being put in the f-block, while the team leader behind the measurement, Tetsuya Sato, says that it doesn't provide enough evidence either way. (Cf. here) So it does seem a somewhat controversial topic after all.
I wonder if there are any chemistry-trained people here that could shed some light on this...
Side note: before the 1940s, Lu was placed with Group 3, so Jensen's position is basically that this was the correct grouping all along. Lawrencium wasn't discovered then, but is right below lutetium.
