Stock, Alfred

The first definitive studies of boron hydrides were carried out by Alfred Stock in Germany starting about 1912 (1). Through extensive and now classic synthetic studies, the field of boron hydride chemistry was founded with the isolation of a series of highly reactive, air-sensitive, and volatile compounds of general composition and This accomplishment required the development of basic vacuum line techniques for the... 

It is also noteworthy that Alfred Stock, who is universally acclaimed as the discoverer of the boron hydrides (1912). " was also the first to propose the use of the term "ligand (in a lecture in Berlin on 27 November 1916). Both events essentially predate the formulation by G. N. Lewis of the electronic theory of valency (1916). It is therefore felicitous that, albeit some 20 years after Stock s death in 1946, two such apparently disparate aspects of his work should be connected in the emerging concept of boranes as ligands . 

The metal itself, having an appreciable vapour pressure, is also toxic, and produces headaches, tremors, inflammation of the bladder and loss of memory. The best documented case is that of Alfred Stock (p. 151) whose constant use of mercury in the vacuum lines employed in his studies of boron and silicon hydrides, caused him to suffer for many years. The cause was eventually recognized and it is largely due to Stock s publication in 1926 of details of his experiences that the need for care and adequate ventilation is now fully appreciated. 

Shortly after 1900, young Alfred Stock began his lifetime work study of the chemistry of boron. He reasoned that this neighbor of the versatile carbon atom could not possibly have the dull and limited chemistry popularly assumed at the time. He entered this study stimulated by his own desire to know—despite advice by the laboratory di-... 

In chemical nomenclature, the oxidation number is sometimes called the Stock number for the German chemist Alfred Stock, who devised this numbering system. Oxidation numbers are discussed in more detail in Sections K and 2.9. 

There are many compounds that contain boron and hydrogen, and they are known collectively as the boron hydrides. Six boron hydrides were prepared by Alfred Stock in 1910-1930 by the addition of hydrochloric acid to magnesium boride that was produced in small amounts when B203 was reduced with magnesium. 

As was discussed in Chapter 13, hydrogen does not react directly with some elements, so the hydrides must be prepared in a different way. Alfred Stock prepared silicon hydrides by first making the magnesium compound, then reacting it with water. 

Interest in the photochemistry of boron compounds dates back as far as 1913 when Alfred Stock investigated the effects of light from a mercury vapor lamp on diboran 6) and on tetraboran 10). In the case of diborane(6) he commented UV light will also decompose B2H6. The volume of a sample in a quartz tube increased by 1/6 after 24 hours exposure to a mercury-arc lamp, and a pale yellow crystalline substance appeared. Stock also observed that B4H q decomposition to B2H is not noticeably influenced by sunlight. 

Alfred Stock (1876-1946) studied the hydrides of some of these metal-like elements. A hydride occurs when hydrogen gains (or shares) an electron rather than losing its single electron when it combines with metals or metallic-like elements. Stock spent years experimenting with boron hydrides (B Hg and BH ), which were used as hydrogen-based rocket fuels powerful enough to lift rockets into space. 

Hexaborane(lO) was among the first boron hydrides isolated by Alfred Stock and his coworkers.1 Until relatively recently, however, B6Hi0 remained unstudied because the lack of adequate preparative methods. Early syntheses suffered either from low yields1 4 or from requirements for starting materials that were difficult to obtain.5 8... 

Nearly a century after Wohler and Bussy liberated beryllium, Alfred Stock and Hans Goldschmidt devised the first commercial process, in which a mixture of the fluorides of beryllium and barium is electrolyzed. The molten beryllium separates out at the water-cooled iron cathode (24). 

Alfred E. Stock. Former director of the Chemical Institute of the Tech-nische Hochschule of Karlsruhe. Former student of Henri Moissan and author of an excellent biographical sketch of him. Visiting lecturer at Cornell University in 1932. He is an authority on the high-vacuum method for studying volatile substances, the chemistry of boron, the preparation and properties of beryllium, and chronic mercurial poisoning. 

Moissan always insisted on extreme neatness in his laboratory, and the wooden floors were waxed every Saturday. Alfred Stock (64) relates that one day Professor Moissan looked critically at the floor and said reproachfully, Who did that Upon careful examination, Dr. Stock noticed that a few drops of water from the tip of his wash-bottle had fallen to the waxed floor (22). 

Borazine has been known since the pioneering work of Alfred Stock early in this century. Stock s work was important in two regards He was the first to study compounds such as the boranes. silanes, and other similar nonmetal compounds, and he perfected vacuum line techniques for the handling of au- and moisture-sensitive compounds, invaluable to the modern inorganic chemist.67 Stock synthesized borazine by heating the adduct of diborane and ammonia 66... 

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