Alfred Stock 175618 224055481 2008-07-07T02:59:10Z Wizardman 713860 per [[WP:UPPI]] {{Infobox Scientist | name = Alfred Stock | image = | birth_date = {{birth date|1876|7|16|df=yes}} | birth_place = [[Danzig]], [[German Empire]] | death_date = {{death date and age|1946|8|12|1876|7|16|df=yes}} | death_place = [[Aken an der Elbe]], [[Germany]] | nationality = [[Germany|German]] | field = [[Chemistry]] | work_institutions = [[University of Karlsruhe]] | alma_mater = | doctoral_advisor = | doctoral_students = [[Egon Wiberg]] | known_for = | author_abbrev_bot = | author_abbrev_zoo = | influences = | influenced = | prizes = | footnotes = }} '''Alfred Stock''' ([[July 16]] [[1876]] – [[August 12]] [[1946]]) was a [[Germany|German]] [[inorganic chemistry|inorganic]] [[List of chemists|chemist]]. He did pioneering research on the [[hydride]]s of [[boron]] and [[silicon]], [[complex (chemistry)|coordination chemistry]], [[mercury (element)|mercury]], and [[mercury poisoning]]. The German Chemical Society's Alfred-Stock Memorial Prize is named after him. ==Life== Born in Danzig ([[Gdańsk]]) and educated at [[Berlin]], he was nine years assistant of [[Emil Fischer]] before he became professor at the [[University of Breslau]] in 1900. In 1916 he succeeded [[Richard Willstätter]] as director at the [[Kaiser Wilhelm Institute for Chemistry]] in Berlin. After a severe mercury poisoning he became the director of the Chemistry Department at the [[University of Karlsruhe|Technische Hochschule in Karlsruhe]] from [[1926]] to [[1936]]. He was renowned for his pioneering research on boron hydrides.<ref>{{cite book |last= Stock |first=Alfred |year = 1933|title = The Hydrides of Boron and Silicon| edition = |publisher = Cornell University Press |location = New York| id = | page= }}</ref> ==Research on the hydrides of boron and silicon== Stock began studying the boron [[hydride]]s - the [[boron]] [[hydrogen]] [[chemical compound]]s with general formula B<sub>x</sub>H<sub>y</sub> - since [[1909]] at [[Breslau]]. Due to their extreme reactivity and flammability in air, boron hydrides could not be purified until his development of methods for separation using high-vacuum manifolds around 1912. He performed similar work on the [[hydride]]s of silicon. The hydrides of boron and silicon represented the first family of binary compounds to approach the richness of hydrocarbons in terms of structural diversity. Not only did the boron hydrides exhibit challenging properties, their structures were also unusual. Elucidation of the structures and the associated bonding models dramatically expanded the scope of inorganic chemistry. Boron hydrides such as [[diborane]] later developed into a range of [[reagent]]s for [[organic synthesis]] as well as a source of diverse ligands and building blocks for researchers. ==Research on other areas of inorganic chemistry== In [[1921]], he first prepared metallic [[beryllium]] by electrolyzing a fused mixture of [[sodium]] and beryllium [[fluorides]]. This method made beryllium available for industrial use, as in special alloys and glasses and for making windows in X-ray tubes. He was also influential in [[complex (chemistry) | coordination chemistry]]. The term "[[ligand]]" (from ''ligare'' [[Latin]], to bind) was first used by Stock in [[1916]].<ref>{{cite journal |first=William H. |last=Brock |coauthors=K. A. Jensen, Christian Klixbüll Jørgensen, [[George B. Kauffman]] |title=The origin and dissemination of the term “ligand” in chemistry |journal=Polyhedron |volume=2 |issue=1 |year=1983 |pages=1–7 |doi=10.1016/S0277-5387(00)88023-7 }}</ref> H. Irving and R.J.P. Williams adopted the term in a paper published in 1948.<ref>{{cite journal |first=H. |last=Irving |coauthors=R.J.P. Williams |title=Order of stability of metal complexes |journal=[[Nature (journal)|Nature]] |year=1948 |volume=162 |pages=746–747 |issn=0028-0836 |doi=10.1038/162746a0 }}</ref> Monodentate, bidentate, tridentate characterized the number of ligands attached to a metal. Given the introduction of ligand concept, he was also able to further derive the idea of [[bite angle]] and other aspects of [[chelation]]. The "Stock system," first published in [[1919]], was a means of nomenclature on [[binary compound]]s. 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 system to be adopted with some accommodations. FeCl<sub>2</sub>, 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 agreed to the use of [[Roman numerals]] but preferred keeping the hyphen and dropping the parentheses. Although this suggestion has not been followed, the Stock system remains in use worldwide. ==Interests in mercury and mercury poisoning== He published over 50 papers on different aspects of [[mercury (element)|mercury]] and [[mercury poisoning]].<ref name="wiberg">{{cite journal | first = Egon | last = Wiberg | authorlink = Egon Wiberg | title = Alfred Stock 1876-1946 | journal = [[Chemische Berichte]] | volume = 83 | issue = 6 | pages = XIX | year = 1950 | doi = 10.1002/cber.19500830619 }}</ref> He also introduced sensitive tests and devised improved laboratory techniques for dealing with mercury which minimized poisoning risk, possibly initiated by his chronic mercury poisoning in [[1923]]. He became more vocal on protesting the mercury usage after realizing the toxicity of its organic derivatives. German [[dentistry|dentists]] abandoned his warning in [[1928]] against copper [[amalgam]] usage. Nevertheless a paper from Fleischmann, in which removal of mercury in amalgam-related illness had led to complete recovery, supported his idea. (''Deutsche Medizinische Wochenschrift'' 1928, No. 8). A committee was founded in Berlin to investigate cases of possible mercury intoxication and hence the term [[micromercurialism]] was first used.<ref>{{cite journal |last=Stock |first=Alfred |title=Die Gefaehrlichkeit des Quecksilberdampfes |journal=Zeitschrift für angewandte Chemie |pages=461–466 |volume=39 |year=1926 |doi=10.1002/ange.19260391502}}</ref> ==Retirement and death== After retirement 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. ==Posthumous recognition== In recognition of his contributions to the field of inorganic chemistry, the German Chemical Society ([[:de:Gesellschaft Deutscher Chemiker|Gesellschaft Deutscher Chemiker]]) posthumously created in 1950 the [[Alfred Stock Memorial Prize]]. The prize, consisting of a gold medal and money, is awarded annually for "an outstanding independent scientific experimental investigation in the field of inorganic chemistry."<ref name="GDCh"> {{cite web |title=Gesellschaft Deutscher Chemiker e.V., GDCh-Preise 2008 |publisher=''[[:de:Gesellschaft Deutscher Chemiker]]'' |year=2007 |url=http://www.gdch.de/gdch/eps/ausschr/aus_2006__e.htm}}</ref> ==References== {{reflist}} ==External links== *{{de icon}} [http://www.gdch.de/gdch/eps/preise/stock.htm List of recipients of the Alfred-Stock-Gedächtnispreis] {{DEFAULTSORT:Stock, Alfred}} [[Category:1876 births]] [[Category:1946 deaths]] [[Category:German chemists]] [[de:Alfred Stock]] [[fr:Alfred Stock]] [[pl:Alfred Stock]] [[sq:Alfred Stock]]