(Born: 24 April 1817; Died: 15 April 1894) French mineralogist & chemist.
Jean-Charles Galissard de Marignac from Geneva, was a pupil of Liebig. It was in Liebig's Giessen laboratory that de Marignac did his only researches on organic chemistry, on naphthalene and phthalic acid. He then changed to anorganic chemistry and commenced his carreer as professor of chemistry first at the Academy of Geneva, which was later to be made into the University.
1. French, 1902 [Collected works].
Jean-Charles Galissard De Marignac | [double rule] | Œuvres Complètes | Publiées Hors Série Sous Les Auspices De La | Société De Physique Et D'Histoire Naturelle De Genève | Par | E. Ador | [rule] | Tome I | [rule] | Notice Biographique - Travaux Divers | 1840-1860 | [ornate rule] | Éditeurs: | [Next text in 3 columns separated by vertical rules:] Ch. Eggimann & Cie | Genève | [vertical rule] | Masson & Cie | Paris | [vertical rule] | Friedlander & Fils | Berlin.
[Vol 1] 4°: , [i]-lvi, -701,  p.
[Vol 2] 4°: , -839,  p. With a fine portrait and numerous plates and folding tables.
Rare. REWORK COMMENTARY.
Edited by Emile Ador [1845- ]. In 1878 Marignac was able to show that the rare earth known as erbia, obtained from gadolinite, could be decomposed into two oxides, one for which the name erbia was retained and a second which was called ytterbia. His most important work, however, consisted in the determination of the atomic weights of numerous elements, and in other subjects of inorganic chemistry. These two volumes contain his numerous papers on inorganic chemistry and crystallography. In his most important, he showed that fluostannates and fluosilicates are isomorphous, thus establishing the formula of silica as SiO2 and not SiO3, and this produced a revolution in chemical mineralogy.
His 111 published papers were handsomely reprinted as Oeuvres completes with portrait and a complete list of Marignacs atomic weights. When, in 1860, Stas dismissed Prout's law as an "illusion", Marignac cautioned that deviations from the law of definite proportions might sometimes occur - a possibility suggested by an erroneous view of the composition of acids which he then held. More speculatively, he suggested that Prout's law might be an "Ideal" law which was subject to perturbing influences such that the weights of the subatomic particles of the primordial matter did not add up to exactly the experimentally determined atomic weights. This daring speculation was revived in 1915 by W.D. Harkins and E.D. Wilson and from it the concept of the packing fraction was developed by F.W. Aston in 1920.
Bibliographical references: DSB: 9, 109. Findlay, Alexander., A hundred years of chemistry. London, G. Duckworth, 1937. 352 p., diagrams: p. 190. Partington, History of Chemistry, 1961-70: 4, 875.