Some Peculiar Double Salts of Lead 3 



color. The present paper will describe the results obtained 

 with the iodid. 



THEORETICAL 



Carius^ describes the preparation of a class of compounds of 



the general formula Pb<i^ rr /^ . where x may be either chlorin, 



bromin, or iodin. To obtain these, he heated together, in a sealed 

 tube, lead acetate and some alkyl-halid, e. g., ethyl, methyl, or 

 methylene chlorid. On heating to a proper temperature, reac- 

 tion takes place, yielding an alkyl-acetate and what he calls chlor- 

 acetin of lead in a crystallized state. Schorlemmer- prepared 

 in like manner lead hexylacetochlorid, thus substantiating Ca- 

 rius's work ; the same has been done in this investigation by 

 repeating the experiments of Carius. 



In attempting an explanation of this reaction, it is possible 

 to make use of the results of von Ende's'^ observations upon the 

 ionic dissociation of the halogen salts of lead. In this he has 

 shown that these salts dissociate in two stages, e. g., PbCh = 

 PbCl-^C and then PbCl-=Pb--^Cl' ; the first stage of ioniza- 

 tion takes place much more readily than the second. It seems 

 reasonable to suppose that this same argument applies to the 

 other salts of lead, in which case the formation of compounds 



CI 

 like Pb<i 7- TT ^ can be readily understood, for : 



Pb<^^^'^'=PbCiHz02- + GHzO-2' . 

 LirizU-2 



This first dissociation would take place with comparative ease, 

 the second less readily, being hindered furthermore by the 

 presence of acetic acid — glacial acetic acid being always used 

 as a solvent; the positive ion PbCiH-sOi' could then com- 

 bine with the more negative CV ion, forming the compound 



CI 

 Pb<z: TTr^ The reaction is probably reversible, that is, 

 C2/73C2. 



•^Ann. Ghent. (Liebig), CXCIX, 142 (1879). 

 ^Ztschr. Anorg. Chetn., XXVI, 129 (1901). 



309 



