# Talk:Lawrencium

Which is the energy gap between states? If the d-configuration is only some 0.01 eV above the p-configuration, then practically the atom has no definite ground state. Incnis Mrsi (talk) 08:13, 16 August 2019 (UTC)

@Incnis Mrsi:: according to this paper (10.1140/epjd/e2007-00136-3), the lowest 6d7s2 level has calculated excitation energy 1331 cm−1, i.e. 0.1650 eV. Double sharp (talk) 10:25, 16 August 2019 (UTC)
Then comparisons against Lu and La are based on the Mendeleyev–Madelung dogma only, whereas IRL the atom looks to be something like thallium, albeit lacking  d10 which is virtually non-functional in this context. Incnis Mrsi (talk) 12:05, 16 August 2019 (UTC)
@Incnis Mrsi: Not really. Chemical bond energies can go to several eV (C≡O is 11.16 eV), and the difference between the d- and the p-configuration is well within that. What is known of Lr chemistry is very much like Lu and not at all like Tl: there is no Lr(I) that would parallel Tl(I). Lr(II) and Lr(III) compounds usually parallel Lu(II) and Lu(III) componds (only Lr(III) is known experimentally while Lr(II) is calculated); [LrII(C5H4SiMe3)3]− is even expected to have a valence configuration of 6d1 for Lr, as described in the article. It seems from calculations (and partly from experiment for Lr) that although Lr and E121 both have anomalous s2p configurations where we would expect something else, it doesn't seem to affect ther chemistry much, which is that of a good eka-Lu and eka-Ac respectively, not that of heavier congeners to Tl. Thorium has a 6d2 7s2 configuration in the ground state, with the first 5f electron appearing only at 0.966 eV, but no one doubts that Th is an f-block metal (it is even 5f1 in the +3 state). Double sharp (talk) 14:27, 16 August 2019 (UTC)
Wait… how far from the ground is 6p of lutetium? The same site claims it is within some 0.51 eV against 2.07 for thulium, 2.14 for ytterbium, 1.74 for hafnium, and 2.15 for tantalum. Seems that Lu can normally use the p-subshell for chemistry? If it can, then yes, we can agree that the two elements are congeners, and Lu with its little family is in some respect different from neighboring groups. Incnis Mrsi (talk) 16:43, 16 August 2019 (UTC)
… and 1.30 for yttrium. Lu and Lr are no members of group 3, dammit. It is rather lanthanum (having the nearest 6p at 1.64 eV) a congener of yttrium. Incnis Mrsi (talk) 16:58, 16 August 2019 (UTC)
The trend of the p-configurations lowering down the table seems to be shared with group 4: for Hf, 5d26s16p1 is at 1.74 eV, but for Rf 6d17s27p1 is expected to be at around 0.3 eV (10.1103/PhysRevLett.74.1079). (For Zr, 4d25s15p1 is at 1.83 eV, and for Ti, 3d24s14p1 is at 1.97 eV.) For a while it was actually also not certain if Rf had a 7p electron in the ground state or not. For the next groups we have Nb 2.07, Ta 2.15; Mo 3.18, W 2.40; Tc 2.04, Re 2.35; Ru 3.13, Os 2.80; Rh 3.36, Ir 3.26; Pd 4.22, Pt 3.74; Ag 3.66, Au 4.63; Cd 3.73, Hg 4.67. Due to relativistic stabilisation of 7p1/2 I would guess that at least some of these trends might drop precipitously for the 6d elements like we see for Rf. From what we know and have predicted it seems that the 6d elements are not actually that different from the 5d ones in spite of this: the homology only gets really bad at Nh. (It also does not seem to make much difference for Lu and Lr which act exactly like any other late lanthanide and actinide respectively.) So I wouldn't say that Lu and Lr in group 3 are ruled out by this (or else we'd have to say Rf is ruled out of being in group 4); group and block assignment is more about properties, and Lu and Lr act more like the other nine 5d and 6d metals than La and Ac do (because of f-contractions). Double sharp (talk) 03:53, 17 August 2019 (UTC)

An editor has asked for a discussion to address the redirect Laurentium. Please participate in the redirect discussion if you wish to do so.  Steel1943 (talk) 19:52, 20 September 2019 (UTC)

This seems to be a historical name suggestion. A Chemistry Stack Exchange answer quotes some past IUPAC deliberations from 1963 about it. I just haven't added it to the article because I can't find the original source. Double sharp (talk) 01:51, 6 November 2022 (UTC)