TRANSACTIONS OF SECTION B. lOT 



2. Does Magnesuim form Alhjl Compounds ? 



By Orme Masson, M.A., D.Sc. 



Mr. Wilsmore has described fully the many attempts which 

 he has made to prepare magnesium ethide.* Having closely 

 watched his work while it was in progress, I have been 

 fully convinced by the results of these experiments that 

 it is not possible to prepare this compound, at all events by 

 the action of magnesium on ethyl iodide. As this result is 

 in direct antagonism to the statements of all the text-books, 

 which are based on Cahours's work of thirty years ago, some 

 comment seems called for. 



Magnesium most certainly does not act on ethyl iodide at 

 the ordinary temperature, as stated by Cahours, and also by 

 Hallwachs and Schafarik. At the boiling-point of the liquid 

 its action is slow, but gradually becomes complete ; but only 

 magnesium iodide and hydrocarbons are formed. According 

 to Cahours, the action takes place at the ordinary temperature 

 so strongly that artificial cooling has to be resorted to, and at 

 higher temperatures in sealed tubes magnesium ethide is pro- 

 duced. It is an unfortunate fact that this latter statement 

 was not tested more conclusively by analysis. As a matter of 

 fact, no estimation was made of the magnesium, nor can we 

 gather from the original memoir that even a qualitative test 

 was applied to the products of combustion, or of the decom- 

 position by water. The percentages of carbon and hydrogen 

 found were such as might be obtained from an impure specimen 

 of magnesium ethide ; but, standing alone, as they do, they are 

 not even an approach to a proof that such a compound had 

 been formed. It seems just possible that Cahours was really 

 dealing with impure zinc ethide, due to his magnesium contain- 

 ing zinc, and this might also account for the action beginning 

 in the cold. However this may be, there is no record, apart 

 from Cahours's, of the actual preparation of magnesium ethide 

 or any other alkyl compound of the metal ; and, until there is 

 such a record, Mr. Wilsmore's complete failure to obtain even 

 a trace of the compound appears to me to necessitate an 

 erasure from the text-books. 



It was pointed out by Mendeleeff that the power of forming 

 alkyl compounds is characteristic only of certain groups of 

 elements. It, in fact, characterizes those elements which 

 occur on the ascending portions of Lothar Meyer's curve of 

 atomic volumes, but not those on the descending portions. 

 This is true at least of the long periods, but the two short 

 periods have been reckoned exceptional. In these short 



* See next paper. 



