some new evidence in favor of group 3 as Sc Y Lu Lr and Conference Announcement

[ERIC SCERRI]

See the final parts of this highly technical article.

p. 8573 bottom left corner.

[Larry T.]

Thank you!

Let's see how long it will take for Rene to come back with a refutation.

On Tue, Oct 21, 2025 at 9:18 PM ERIC SCERRI <sce...@g.ucla.edu> wrote:

See the final parts of this highly technical article.

p. 8573 bottom left corner.

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Incidentally, I don't recall whether I mentioned this before, I am organizing the next international conference for the Society for the Philosophy of Chemistry here at UCLA, for July 29th-31st, 2026.  Lectures will be held in Rpyce Hall, pictured below in the link.

This is an initial announcement.  See the society website for updates.

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ERIC SCERRI

UCLA

Website: http://www.ericscerri.com
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Founder & Editor-in-Chief of Foundations of Chemistry 

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[Scott Hutcheon]

Without further/complete data points (full 4f-5f and 6d Carbides, or at least full 3d-4d-5d Carbides), would be hesitant to claim this little/incomplete information (see Shannon) as proof of victory in the ongoing Scylac-Scylur Skirmish -- as there is very little consistent/non-existent Group smoothness/trends down either the artificially stacked d-blocks of the current locally-correct-only (non-Copernican Principle) standard PT or the correctly placed d- and f-periods of the CSPT and RSPT (especially if chemists ever want to be taken as seriously as physicists), except of course for inconsistencies expected around the properly placed Column of Instability.

Should also be weighted against other work by one of the same authors:

https://www.researchgate.net/figure/Bond-dissociation-energies-of-the-lanthanide-chalcogenides-LnO-LnS-and-LnSe-as-a_fig2_350356848

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[Rene]

On 23 Oct 2025, at 00:54, Larry T. <ora...@gmail.com> wrote:

Thank you!

Let's see how long it will take for Rene to come back with a refutation.

On Tue, Oct 21, 2025 at 9:18 PM ERIC SCERRI <sce...@g.ucla.edu> wrote:

See the final parts of this highly technical article.

p. 8573 bottom left corner.

Thank you Larry; good to hear from you. And thanks Eric for bringing this article to our attention.

Briefly, my assessment is that the evidence the authors (T&M) rely on is contradictory, and too limited and scattered to support their claim. Augmenting their data points suggests that La, rather than Lu, provides the better fit for Group 3. (Yes, I was quite surprised by this.)

That they cite Jensen (1982) as supporting evidence is also telling. Those who continue to cite that paper in favour of Sc-Y-Lu have not done their homework. As Eric and Parsons (2018) rightly concluded, Jensen was too selective in the evidence he presented.

Scerri ER, Parsons W 2018, What elements belong in Group 3 of the periodic table? In: Scerri E, Restrepo G (eds) Mendeleev to Oganesson: A multidisciplinary perspective on the periodic table, pp. 140–151, Oxford University Press, New York

Please find my analysis below—longer than a sound bite, but I hope appropriately so.

What do you now make of all this Larry?

René

Analysis

The passage at the bottom left corner of p. 8573 says:

Another issue that arises in the 5d series concerns which metal should be considered the group 3 member of this series. The candidates are La, with its [...]5d1 6s2, 2D3/2g ground level and Lu, with its [...]4f14 5d1 6s2, 2D3/2g ground level. [A] Table 6 and Figure 10 clearly show that LuC follows that pattern of the 3d and 4d series of transition metal carbides, while [B] the BDE of LaC is anomalously high. As all the remaining members of the 5d transition metal series have the 4f subshell filled, it seems that Lu has more in common with the remaining 5d metals while [C] La has more in common with the subsequent lanthanides (Ce, Pr, Nd, …).

Re [A], "...Figure 10 clearly show[s] that LuC follows that pattern of the 3d and 4d series of transition metal carbides", this is not the case: the 3d and 4d series show no simple or consistent patterns. Furthermore, Figure 10 spans only groups 3 to 10; to gain a fuller picture, Groups 2, 11, and 12 would need to be included.

Re [B], "the BDE of LaC is anomalously high." This is correct, but the series ScC, YC, and LaC (or LuC) each contain only three data points, and their bond-dissociation energies—3.04, 3.42, 4.72, and 3.69 eV respectively—are too few and too scattered to be decisive.

When, however, the BDEs of the broader cross-block sequence BC → AlC → ScC → YC → LaC (or LuC) are plotted against atomic number, the smoothness of the trendlines differs markedly. Second-order polynomial fits give R² = 0.739 for LaC and R² = 0.323 for LuC. On the presumption that the smoother the trendline, the better the fit in periodic-law terms, the sequence terminating in LaC provides the superior correspondence. I have attached the two charts in question.

Re [C]—“it seems that... La has more in common with the subsequent lanthanides (Ce, Pr, Nd, …)” This is contradicted by Merriles et al. (2023, p. 9596)—whom T&M cite—who write: “there is a significant variation in the bond strengths of LaC (4.718(4) eV), CeC (4.893(3) eV), PrC (4.052(3) eV), and NdC (3.596(3) eV), even though the molecules have almost identical ground-state electronic configurations.”

Conclusion: T&M’s claims, as far as the composition of Group 3 is concerned, do not hold water.

Merriles DM et al. 2023, Probing the chemical bond between lanthanides and carbon: CeC, PrC, NdC, LuC, and TmC2, Inorg. Chem. 62, pp. 9589−9601

[Rene]

On 23 Oct 2025, at 04:46, Scott Hutcheon <scotth...@gmail.com> wrote:

Without further/complete data points (full 4f-5f and 6d Carbides, or at least full 3d-4d-5d Carbides), would be hesitant to claim this little/incomplete information (see Shannon) as proof of victory in the ongoing Scylac-Scylur Skirmish -- as there is very little consistent/non-existent Group smoothness/trends down either the artificially stacked d-blocks of the current locally-correct-only (non-Copernican Principle) standard PT or the correctly placed d- and f-periods of the CSPT and RSPT (especially if chemists ever want to be taken as seriously as physicists), except of course for inconsistencies expected around the properly placed Column of Instability.

Thank you Scott.

I tend to agree with you about the need for further data points.

Re: "very little consistent/non-existent Group smoothness/trends down either the artificially stacked d-blocks of the current locally-correct-only (non-Copernican Principle) standard PT", I disagree.

For group 3 for example, it is easy enough to construct XY scatter plots of physical or chemical properties vs Z going down either B-Al-Sc-Y-La or B-Al-Sc-Y-Lu, and to assess the smoothness of the resulting trendlines.

Of course, group 3 is Sc-Y-La-Ac or Lu-Lr, whereas B-Al are in group 13. Nevertheless, the trends going down B-Al-Sc-Y-La are smoother than those going down B-Al-Ga-In-Tl.

For the 40 physical or chemical properties I have plotted, many of the resulting trendlines have smoothness values in the 0.90+ range. Conversely, the two plots of electrical conductivity are down in the 0.10’s.

The average smoothness of the 40 trendlines is 0.75 for -La and 0.69 for -Lu.

René