The INTERNET Database of Periodic Tables

There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database holds information on periodic tables, the discovery of the elements, the elucidation of atomic weights and the discovery of atomic structure (and much, much more).

Use the drop menus or search box (below) to Select or Search the 1400 entries in the database:

Year: 1858

PT id = 1047, Type = formulation review element weight structure

Cannizzaro's Letter or Sunto

Letter of Professor Stanislao Cannizzaro to Professor S. De Luca: Sunto di un corso di filosofia chimica (Sketch of a Course of Chemical Philosophy) given in the Royal University of Genoa, Il Nuovo Cimento, vol. vii. (1858), pp. 321-366.

Many thanks to Carmen Giunta, Professor of Chemistry Emeritus, Le Moyne College who provided the information about, and link to, Cannizzaro's Letter. See a list of other classic chemistry papers.

Read the full letter/paper, in English translation, here. (The Italian version is here.)

Cannizzaro writes:

"I believe that the progress of science made in these last years has confirmed the hypothesis of Avogadro, of Ampère, and of Dumas on the similar constitution of substances in the gaseous state; that is, that equal volumes of these substances, whether simple or compound, contain an equal number of molecules: not however an equal number of atoms, since the molecules of the different substances, or those of the same substance in its different states, may contain a different number of atoms, whether of the same or of diverse nature."

From the Science History of Science Institute:

"In 1858 Cannizzaro outlined a course in theoretical chemistry for students at the University of Genoa,where he had to teach without benefit of a laboratory. He used the hypothesis of a fellow Italian, Amedeo Avogadro, who had died just two years earlier, as a pathway out of the confusion rampant among chemists about atomic weights and the fundamental structure of chemical compounds."

Mark Leach writes:

"Before a periodic table of the chemical elements – which orders the elements by atomic weight and then groups them by property – could be developed it was necessary to know the atomic weight values. However, to deduce the atomic weights was a problem as it was necessary to know the ratios of how the elements combined, the stoichiometry.

"Tables of atomic weight data by Dalton (1808), Wollaston (1813), Daubeny (1831) and Kopp & Will (1858) show progress, but the 1858 Cannizzaro letter was the first where the atomic weight data is more or less both complete and accurate, thus removing stiochiometric errors.

"I have extracted the element atomic weight data from the paper, and given the % error with respect to modern atomic weight/mass data. Only titanium is significantly out! It is clear that Cannizzaron knew that hydrogen, nitrogen, oxygen, chlorine, bromine & iodine existed as diatomic molecules."

Element	Symbol	Cannizzaro's Weight	Modern Weight/Mass	% error
Hydrogen	H	1	1.008	-0.8%
Boron	B	11	10.81	1.7%
Carbon	C	12	12.011	-0.1%
Nitrogen	N	14	14.007	0.0%
Oxygen	O	16	15.999	0.0%
Sodium	Na	23	22.99	0.0%
Magnesium	Mg	24	24.305	-1.3%
Aluminium	Al	27	26.982	0.1%
Silicon	Si	28	28.085	-0.3%
Sulphur	S	32	32.06	-0.2%
Phosphorus	P	32	30.974	3.2%
Chlorine	Cl	35.5	35.45	0.1%
Potassium	K	39	39.098	-0.3%
Calcium	Ca	40	40.078	-0.2%
Chromium	Cr	53	51.996	1.9%
Manganese	Mn	55	54.938	0.1%
Iron	Fe	56	55.845	0.3%
Titanium	Ti	56	47.867	14.5%
Copper	Cu	63	63.546	-0.9%
Zinc	Zn	66	65.38	0.9%
Arsenic	As	75	74.922	0.1%
Bromine	Br	80	79.904	0.1%
Zirconium	Zr	89	91.224	-2.5%
Silver	Ag	108	107.87	0.1%
Tin	Sn	117.6	118.71	-0.9%
Iodine	I	127	126.9	0.1%
Barium	Ba	137	137.3	-0.2%
Platinum	Pt	197	195.08	1.0%
Mercury	Hg	200	200.59	-0.3%
Lead	Pb	207	207.2	-0.1%

Diatomic Molecule	Formula	Cannizzaro's Weight	Modern Weight/Mass	% error
Hydrogen	H₂	2	2.016	-0.8%
Oxygen	O₂	32	31.998	0.0%
Sulphur	S₂	64	64.12	-0.2%
Chlorine	Cl₂	71	70.9	0.1%
Bromine	Br₂	160	159.808	0.1%
Iodine	I₂	254	253.8	0.1%

Molecule	Formula	Cannizzaro's Weight	Modern Weight/Mass	% error
Water	H₂O	18	18.015	-0.1%
Hydrochloric Acid	HCl	36.5	36.458	0.1%
Methane	CH₄	16	16.043	-0.3%
Hydrogen sulphide	H₂S	34	34.076	-0.2%
Diethyl ether	CH₃CH₂OCH₂CH₃	74	74.123	-0.2%
Carbon disulphide	CS₂	76	76.131	-0.2%
Chloroethane	CH₃CH₂Cl	64.5	64.512	0.0%

Below is a list of the elements showing which ones were included by Cannizzaro and which one were ommitted (because they had not been discovered) or are strangely missing. Odd ommissions (to the modern eye) include: Lithium, Beryllium, Cobalt, Nickel, Palladium, Tungsten and Gold.

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