METALS AND METALLOIDS 711 



4. Organo-metallic and Organometalloidal Radicals 

 behaving as complex alkali metals 



A necessarily brief and imperfect survey has now been made 

 of all the families of metals and metalloids capable of yielding 

 organic derivatives. It will have been noticed that in several 

 instances, for example with certain derivatives of arsenic, 

 mercury, and thallium, it is possible to obtain complex alkaline 

 hydroxides having the properties of caustic soda or potash. 



The alkali metals, potassium, lithium, sodium, rubidium, 

 and caesium, are distinguished from most other metals by 

 their univalency and by their property of yielding very 

 soluble alkaline hydroxides. Moreover, they are distinguished 

 from all other elements by having each in its own horizontal 

 series the maximum atomic volume. When this property 

 (atomic volume) is plotted for all the elements against the 

 atomic weight as was done by Lothar Meyer, it is seen that the 

 alkali metals occupy points of maxima on the curve. 



The study of organic derivatives of metals, metalloids, and 

 non-metals shows that one can synthesise a compound alkali 

 metal by associating with many polyvalent elements sufficient 

 alkyl or aryl radicals to reduce the principal valency to unity. 

 If the remaining valency is satisfied by iodine, the result is a 

 saline iodide in which the iodide ion can be replaced by 

 hydroxyl, usually through the agency of moist silver oxide, 

 giving rise to a basic hydroxide which in the majority of cases 

 is soluble in water to a caustic alkaline solution. The following 

 series of organo-metallic, organo-metalloidal, and organo-non- 

 metallic hydroxides illustrates this principle : 



N(CH 3 )40H, P(C 2 H 5 ) 4 OH, As(C 7 H 7 ) 4 OH, Sb(CH 3 ) 4 OH, 

 Se(CH 3 ) 3 OH, Sn(C 2 H 5 ) 3 OH, Pb(C 2 H 5 ) 3 OH, Pt(CH 3 ) 3 OH, 



I(C G H 5 ) 2 OH, Tl(CH 3 ) 2 OH, 



Hg(C 2 H 5 )OH Hg(C 6 H 5 )OH. 



All these substances, with the exception of trimethyl- 

 platinic hydroxide, are soluble in water, giving rise to strongly 

 alkaline solutions, which absorb carbon dioxide, precipitate the 

 heavy metals from their soluble salts, and saponify fats, thus 

 behaving quite like the strong caustic alkalis, sodium and 

 potassium hydroxides. 



Providing that the univalent complex organo-metallic or 

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