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| MICROMERCURIALISM given us by Alfred Stock |
Alfred Stock (1876-1946) a German chemist and first published in 1919. was born in 1876, and when he retired in 1936 he moved from Karlsruhe to Berlin. He died at Aken an der Elbe, a small town near Dessau, in August 1946 at the age of 70. The term ligand (ligare [Latin], to bind) was first used by Alfred Stock in 1916 in relation to silicon chemistry. The first use of the term in a British journal was by H.Irving and R.J.P. Williams in Nature, 1948, 162, 746. For a fascinating review of the origin and dissemination of the term 'ligand' in chemistry see: W.H. Brock, K.A Jensen, C.K. Jorgensen and G.B. Kauffman,Polyhedron, 2, 1983, 1-7. Ligands can be further characterised as monodentate, bidentate, tridentate etc. Where the concept of teeth (dent) is introduced, hence the idea of bite angle etc. A binary compound is one made of two different elements. There can be one of each element such as in CuCl or FeO. There can also be several of each element such as Fe2O3 or SnBr4. It is called the Stock system or Stock's system. It was designed by Alfred Stock and first published in 1919. In his own words, he considered the system to be "simple, clear, immediately intelligible, capable of the most general application." In 1924, a German commission recommended Stock's system be adopted with some changes. For example, FeCl2,which would have been named iron(2)-chloride according to Stock's original idea, became iron(II) chloride in the revised proposal. In 1934, Stock approved of the Roman numerals, but felt it better to keep the hyphen and drop the parenthesis. This suggestion has not been followed, but the Stock system remains in use world-wide. The term chelate was first applied in 1920 by Sir Gilbert T. Morgan and H.D.K. Drew [J. Chem. Soc., 1920, 117, 1456], who stated: "The adjective chelate, derived from the great claw or chela (chely- Greek) of the lobster or other crustaceans, is suggested for the caliperlike groups which function as two associating units and fasten to the central atom so as to produce heterocyclic rings." Metal complexation is of widespread interest. It is studied not only by inorganic chemists, but by physical and organic chemists and by biochemists, pharmacologists, molecular biologists and environmentalists. In 1928 Alfred Stock warned against copper amalgam, which he noted was being abandoned in German dentistry at the time. He also referred to a paper by Professor Fleischmann, who described a number of cases of amalgam related illness in which removal of amalgam had led to complete recovery (Deutsche Medizinische Wochenschrift 1928, No. 8). These findings had been made at a special unit in Berlin which was established to investigate cases of possible mercury intoxication. Hence the term micromercurialism was first used by Alfred Stock. |
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