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A New Class of Orgcmo-Tin Compomuh. [Apr. 20, 



(2) is similar to that suggested by Pfeiffer,* in order to 

 M that he obtained diethylstannimethylene oxide msteml 

 io acid by the action of ethyl iodide on sodium 



St Tnumber of attempts were made to prepare salts of methylstann- 

 oxvlicacid but these have been uniformly unsuccessful owing to the 

 acidic characters of the substance. The a, die 



methylstannoxylic acid are, in fact, so very slight that 

 tend" to react in the ortho-form rather than in the 

 tlnoxylic condition, although the reverse is true m the case of 

 carboxylic acids. Thus, on treating methylstannoxylic acid with 

 nceJrated hydriodic acid, it is immediately converted into ^methy 1- 

 stanniodoform, so that the reaction, by means of which we -first pre- 

 pared the acid, is a reversible one; since methylstannoxylic acid i 

 very easily prepared in quantity by the action of methyl iodide on 

 alcoholic sodium stannite solution, the most convenient method of 

 preparing the stanniodoform derivative consists in treating methyl- 

 stannoxylic acid with strong hydriodic acid, and, after filtration, 

 crystallising the product from a mixture of benzene and 

 petroleum. 



Methylstannibromoform, CH 3 . SnBr 3 . 



Methylstannoxylic acid dissolves readily in concentrated hydro- 

 bromic acid, and on extracting the solution with light petroleum and 

 evaporating the solvent, methylstannibromoform separates. After 

 crystallisation from petroleum it is obtained in the form of long 

 colourless prisms which melt at 5055 and may be distilled without 

 decomposing. The substance fumes slightly in the air and dissolves 

 to a clear solution in water. Methylstannibromoform is readily soluble 

 in the ordinary organic solvents. The following analytical results 

 were obtained : 



0-4664 gave 0-0563 C0 2 and 0-0382 H- 2 0. C = 3-29. H = 0'91. 

 CH 3 .SnBr 8 requires C = 3'2l and H = 0'80. 



Methylstannichloroform, C 



Methylstannoxylic acid dissolves in concentrated hydrochloric acid 

 with evolution of heat, and, after saturating the solution with anhydrous 

 calcium chloride and extracting with benzene, the benzene solution 

 yields a residue when evaporated which slowly crystallises in the 

 desiccator. On gently warming methylstannoxylic acid in a current 

 of dry hydrogen chloride, reaction occurs and methylstannichloroform 

 distils, condensing in the receiver as a colourless crystalline material. 



* ' Berichte,' vol. 35, p. 3203. 



