Werner was born in 1866 inMulhouse,Alsace (which was then part of France, but which was annexed by Germany in 1871). He was raised asRoman Catholic.[3] He was the fourth and last child of Jean-Adam Werner, a foundry worker, and his second wife, Salomé Jeannette Werner, who originated from a wealthy family.[3] He went to Switzerland to study chemistry at theSwiss Federal Institute (polytechnikum) in Zurich. Still, since this institute was not empowered to grant doctorates until 1909, Werner received a doctorate formally from the University of Zürich in 1890.[3] After postdoctoral study inParis, he returned to the Swiss Federal Institute to teach (1892). In 1893 he moved to theUniversity of Zurich, where he became a professor in 1895. In 1894 he became a Swiss citizen.[3]
In his last year, he suffered from a general, progressive, degenerativearteriosclerosis, especially of the brain, aggravated by years of excessive drinking and overwork. He died in a psychiatric hospital inZürich[3] on 15 November 1919 ofarteriosclerosis at the age of 52.
In 1893, Werner was the first to propose correct structures for coordination compounds containingcomplex ions, in which a central transition metal atom is surrounded by neutral or anionicligands.
For example, it was known that cobalt forms a "complex" hexamine cobalt (III) chloride, with formula CoCl3•6NH3, but the nature of the association indicated by the dot was mysterious. Werner proposed the structure[Co(NH3)6]Cl3, with the Co3+ ion surrounded by six NH3 at the vertices of an octahedron. The three Cl− are dissociated as free ions, which Werner confirmed by measuring theconductivity of the compound in an aqueous solution, and also by chloride anion analysis using precipitation withsilver nitrate. Later,magnetic susceptibility analysis was also used to confirm Werner's proposal for the chemical nature of CoCl3•6NH3.
cis-[Co(NH3)4 Cl2]+trans-[Co(NH3)4 Cl2]+
For complexes with more than one type of ligand, Werner succeeded in explaining the number ofisomers observed. For example, he explained the existence of two tetramine isomers, "Co(NH3)4Cl3", one green and one purple. Werner proposed that these are twogeometric isomers of formula [Co(NH3)4Cl2]Cl, with one Cl− ion dissociated as confirmed by conductivity measurements. The Co atom is surrounded by four NH3 and two Cl ligands at the vertices of an octahedron. The green isomer is "trans" with the two Cl ligands at opposite vertices, and the purple is "cis" with the two Cl at adjacent vertices.
Werner also prepared complexes withoptical isomers, and in 1914 he reported the first syntheticchiral compound lacking carbon, known ashexol with formula [Co(Co(NH3)4(OH)2)3]Br6.
Before Werner, chemists defined thevalence of an element as the number of its bonds without distinguishing different types of bonds. However, in complexes such as [Co(NH3)6]Cl3 for example, Werner considered that the Co-Cl bonds correspond to a "primary" valence of 3 at long distance, while the Co-NH3 bonds which correspond to a "secondary" or weaker valence of 6 at shorter length. This secondary valence of 6 he referred to as thecoordination number which he defined as the number of molecules (here of NH3) directly linked to the central metal atom. In other complexes, he found coordination numbers of 4 or 8.
On these views, and other similar views, in 1904Richard Abegg formulated what is now known asAbegg's rule which states that the difference between the maximum positive and negativevalence of anelement is frequently eight. This rule was used later in 1916 whenGilbert N. Lewis formulated the "octet rule" in hiscubical atom theory.
W. Gregory Jackson; Josephine A. McKeon; Silvia Cortez (2004). "Alfred Werner's Inorganic Counterparts of Racemic and Mesomeric Tartaric Acid: A Milestone Revisited".Inorg. Chem.43 (20):6249–6254.doi:10.1021/ic040042e.PMID15446870.
^"Alfred Werner - Nobel Prize for Chemistry 1913"(PDF).University of Zurich. Retrieved9 December 2022.He moved there with his wife, Emma Wilhelmine, née Giesker, whom he had married on 1 October 1894.
Alfred Werner on Nobelprize.org including the Nobel Lecture, 11 December 1913On the Constitution and Configuration of Higher-Order Compounds
The Nobel Prize in Chemistry 1913 - short article about his work on the linkage of atoms in molecules by which he has thrown new light on earlier investigations and opened up new fields of research, especially in inorganic chemistry.
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