many thanks Mark

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ERIC SCERRI

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Jan 22, 2026, 2:58:19 AM (6 days ago) Jan 22
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Hi Mark,

Thanks for your response concerning Be.

In fact, the page you pointed us to on your website is of even greater interest to me, as I will be speaking at the 100th anniversary of the death of Cannizzaro in Palermo in a few months.  https://cannizzaro2026.unipa.it/program/

Your analysis of the % errors in Cazzizzaro’s atomic and molecular weight are especially helpful.

Best
Eric


Mark Leach

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Jan 22, 2026, 8:24:51 AM (6 days ago) Jan 22
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Hi Eric & All,

Excellent.

As you probably know, Cannizzaro is most famous amongst chemistry students for the “Cannizzaro reaction”, a disproportionation redox reaction where an aldehyde is both oxidised to the corresponding carboxylic acid and reduced to the corresponding alcohol:

2 R-CHO  —>   R-COOH   +  R-CH2OH

However, this pales into insignificance compared with his atomic weight work, which almost few chemists know about (although it is very well known to historians of chemistry.)

Whenever I look at Cannizzaro letter:


I am astonished by the accuracy and precision of the data. Only titanium is significantly “out”.

But, where are lithium and beryllium???

Mark
 
Mark Leach
meta-synthesis




ERIC SCERRI

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Jan 22, 2026, 3:54:14 PM (6 days ago) Jan 22
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Thanks for the further info on Cannizzaro.  Please keep it coming.

This is a part of the history of the periodic table that I am not very familiar with.

Concerning your calculations of errors made by Cannizzaro, relative to modern values of atomic weights.

On your website, you show that his value for Ti represented an error of 14% or so.

However, if you look at the PDF image I sent from Van Spronsen’s book, Cannizzaro’s 1860 value for Ti seems to be 50, which is a good deal closer to the modern value.

Screenshot 2026-01-22 at 12.53.10 PM.png

Which Cannizaro values were you using?  Would you consider recalculating errors for his 1860 values?

Best 
Eric

René

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Jan 23, 2026, 1:17:16 AM (6 days ago) Jan 23
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Hi Mark

Lithium (7) was in Cannizaro according to the van Spronsen table that Eric sent us but I wasn’t able to find it specifically mentioned as such in the English translation of Sunto di un corso di filosofia chimica (1858).

I presume the value for Li was inferred from Sunto?

René

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Mark Leach

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Jan 23, 2026, 10:27:08 AM (5 days ago) Jan 23
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Hi Eric,

In one of the tables I see:


PastedGraphic-1.png

That is two Cl2 (= 142) and  56 “of” titanium.

From the original letter in Italian:



PastedGraphic-2.png


From my reading, the original Cannizzaro letter gives Ti = 56.


Mark

Mark Leach
meta-synthesis





On 22 Jan 2026, at 20:53, ERIC SCERRI <sce...@g.ucla.edu> wrote:

Thanks for the further info on Cannizzaro.  Please keep it coming.

This is a part of the history of the periodic table that I am not very familiar with.

Concerning your calculations of errors made by Cannizzaro, relative to modern values of atomic weights.

On your website, you show that his value for Ti represented an error of 14% or so.

However, if you look at the PDF image I sent from Van Spronsen’s book, Cannizzaro’s 1860 value for Ti seems to be 50, which is a good deal closer to the modern value.

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